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Bibliography on: Sociobiology

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ESP: PubMed Auto Bibliography 03 Aug 2020 at 01:44 Created: 

Sociobiology

Sociobiology is a field of scientific study that is based on the hypothesis that social behavior has resulted from evolution and attempts to examine and explain social behavior within that context. Sociobiology investigates social behaviors, such as mating patterns, territorial fights, pack hunting, and the hive society of social insects. It argues that just as selection pressure led to animals evolving useful ways of interacting with the natural environment, it led to the genetic evolution of advantageous social behavior. While the term "sociobiology" can be traced to the 1940s, the concept did not gain major recognition until the publication of Edward O. Wilson's book Sociobiology: The New Synthesis in 1975.

Created with PubMed® Query: sociobiology NOT pmcbook NOT ispreviousversion

Citations The Papers (from PubMed®)

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RevDate: 2020-07-09

Poelstra J, Salmona J, Tiley GP, et al (2020)

Cryptic Patterns of Speciation in Cryptic Primates: Microendemic Mouse Lemurs and the Multispecies Coalescent.

Systematic biology pii:5869053 [Epub ahead of print].

Mouse lemurs (Microcebus) are a radiation of morphologically cryptic primates distributed throughout Madagascar for which the number of recognized species has exploded in the past two decades. This taxonomic revision has prompted understandable concern that there has been substantial oversplitting in the mouse lemur clade. Here, we investigate mouse lemur diversity in a region in northeastern Madagascar with high levels of microendemism and predicted habitat loss. We analyzed RADseq data with multispecies coalescent (MSC) species delimitation methods for two pairs of sister lineages that include three named species and an undescribed lineage previously identified to have divergent mtDNA. Marked differences in effective population sizes, levels of gene flow, patterns of isolation-by-distance, and species delimitation results were found among the two pairs of lineages. Whereas all tests support the recognition of the presently undescribed lineage as a separate species, the species-level distinction of two previously described species, M. mittermeieri and M. lehilahytsara is not supported - a result that is particularly striking when using the genealogical discordance index (gdi). Non-sister lineages occur sympatrically in two of the localities sampled for this study, despite an estimated divergence time of less than 1 Ma. This suggests rapid evolution of reproductive isolation in the focal lineages, and in the mouse lemur clade generally. The divergence time estimates reported here are based on the MSC calibrated with pedigree-based mutation rates and are considerably more recent than previously published fossil-calibrated relaxed-clock estimates. We discuss the possible explanations for this discrepancy, noting that there are theoretical justifications for preferring the MSC estimates in this case.

RevDate: 2020-07-01

Yordy J, Kraus C, Hayward JJ, et al (2020)

Body size, inbreeding, and lifespan in domestic dogs.

Conservation genetics (Print), 21(1):137-148.

Inbreeding poses a real or potential threat to nearly every species of conservation concern. Inbreeding leads to loss of diversity at the individual level, which can cause inbreeding depression, and at the population level, which can hinder ability to respond to a changing environment. In closed populations such as endangered species and ex situ breeding programs, some degree of inbreeding is inevitable. It is therefore vital to understand how different patterns of breeding and inbreeding can affect fitness in real animals. Domestic dogs provide an excellent model, showing dramatic variation in degree of inbreeding and in lifespan, an important aspect of fitness that is known to be impacted by inbreeding in other species. There is a strong negative correlation between body size and lifespan in dogs, but it is unknown whether the higher rate of aging in large dogs is due to body size per se or some other factor associated with large size. We used dense genome-wide SNP array data to calculate average inbreeding for over 100 dog breeds based on autozygous segment length and found that large breeds tend to have higher coefficients of inbreeding than small breeds. We then used data from the Veterinary medical Database and other published sources to estimate life expectancies for pure and mixed breed dogs. When controlling for size, variation in inbreeding was not associated with life expectancy across breeds. When comparing mixed versus purebred dogs, however, mixed breed dogs lived about 1.2 years longer on average than size-matched purebred dogs. Furthermore, individual pedigree coefficients of inbreeding and lifespans for over 9000 golden retrievers showed that inbreeding does negatively impact lifespan at the individual level. Registration data from the American Kennel Club suggest that the molecular inbreeding patterns observed in purebred dogs result from specific breeding practices and/or founder effects and not the current population size. Our results suggest that recent inbreeding, as reflected in variation within a breed, is more likely to affect fitness than historic inbreeding, as reflected in variation among breeds. Our results also indicate that occasional outcrosses, as in mixed breed dogs, can have a substantial positive effect on fitness.

RevDate: 2020-06-27

Sharma A, Singh P, Sarmah BK, et al (2020)

Quorum sensing: Its role in microbial social networking.

Research in microbiology pii:S0923-2508(20)30057-7 [Epub ahead of print].

Twentieth century observes a huge paradigm shift in the field of sociobiology, which moved from social intelligence of animals to microbes. Quorum Sensing Molecules (QSMs) are the small chemical molecules, which establish the mode of communication among microbes, and is called Quorum Sensing (QS). These molecules are crucial for determining the decisions of large groups of cells, which is a density-dependent process. Thus, this mechanism draws a very thin line between bacteria that are actually prokaryotes and clustered bacteria mimicking as eukaryotes. This review discusses about the designs of microbial communication networks, and the role of QS in plant-microbe interaction.

RevDate: 2020-06-25
CmpDate: 2020-06-25

Davies NM, Howe LJ, Brumpton B, et al (2019)

Within family Mendelian randomization studies.

Human molecular genetics, 28(R2):R170-R179.

Mendelian randomization (MR) is increasingly used to make causal inferences in a wide range of fields, from drug development to etiologic studies. Causal inference in MR is possible because of the process of genetic inheritance from parents to offspring. Specifically, at gamete formation and conception, meiosis ensures random allocation to the offspring of one allele from each parent at each locus, and these are unrelated to most of the other inherited genetic variants. To date, most MR studies have used data from unrelated individuals. These studies assume that genotypes are independent of the environment across a sample of unrelated individuals, conditional on covariates. Here we describe potential sources of bias, such as transmission ratio distortion, selection bias, population stratification, dynastic effects and assortative mating that can induce spurious or biased SNP-phenotype associations. We explain how studies of related individuals such as sibling pairs or parent-offspring trios can be used to overcome some of these sources of bias, to provide potentially more reliable evidence regarding causal processes. The increasing availability of data from related individuals in large cohort studies presents an opportunity to both overcome some of these biases and also to evaluate familial environmental effects.

RevDate: 2020-06-15

Charpentier MJE, Harté M, Poirotte C, et al (2020)

Same father, same face: Deep learning reveals selection for signaling kinship in a wild primate.

Science advances, 6(22):eaba3274.

Many animals rely on facial traits to recognize their kin; however, whether these traits have been selected specifically for this function remains unknown. Using deep learning for face recognition, we present the first evidence that interindividual facial resemblance has been selected to signal paternal kinship. Mandrills (Mandrillus sphinx) live in matrilineal societies, in which females spend their entire lives not only with maternal half-sisters (MHS) but also with paternal half-sisters (PHS). We show that PHS have more differentiated social relationships compared to nonkin, suggesting the existence of kin recognition mechanisms. We further demonstrate that facial resemblance increases with genetic relatedness. However, PHS resemble each other visually more than MHS do, despite both kin categories sharing similar degrees of genetic relatedness. This paternally derived facial resemblance among PHS indicates selection to facilitate kin recognition. This study also highlights the potential of artificial intelligence to study phenotypic evolution.

RevDate: 2020-06-09

Jundi BE (2020)

Underwater Path Integration: Using the Celestial Dome to Get Back Home.

Current biology : CB, 30(11):R639-R642.

A new study shows that mantis shrimp employ path integration, based on celestial and egocentric cues as orientation references, to return to their underwater burrows.

RevDate: 2020-06-08
CmpDate: 2020-06-08

Fina PM, Cunningham FE, Zhao X, et al (2020)

Reporting of adverse drug events in the Veterans Health Administration for patients whose treatment with empagliflozin or apixaban was discontinued.

American journal of health-system pharmacy : AJHP : official journal of the American Society of Health-System Pharmacists, 77(1):22-32.

PURPOSE: To examine the reporting rates of adverse drug events (ADEs) with apixaban and empagliflozin as reports move up to the next level of spontaneous reporting.

METHODS: This was a retrospective cohort study of outpatients who discontinued apixaban or empagliflozin within 3 years of Food and Drug Administration (FDA) approval. We enriched the sample using an active surveillance strategy to identify subsets of patients with International Classification of Diseases (ICD) codes possibly associated with an ADE. Stratified random samples of charts were reviewed to determine if patients discontinued the medication due to an ADE. If so, we ascertained whether these were uploaded into the Veterans Administration (VA) electronic health record reporting system (Adverse Reaction Tracking System [ARTS]), VA national Web-based system (VA Adverse Drug Event Reporting System [VA ADERS]), and FDA MedWatch.

RESULTS: From the cohort of 2,973 patients who discontinued apixaban, 321 patients (10.8%) were randomly sampled for chart review (including 61 patients with relevant ICD codes). During chart review, 88 ADEs were identified, with 40/61 (65.6%) from the subset with ICD codes. Of the total of 88 ADEs, 18.2%, 10.2%, and 6.8% were reported in ARTS, VA ADERS, and MedWatch, respectively. Of the 1,555 patients who discontinued empagliflozin, 179 patients (11.5%) were randomly sampled for chart review (40 patients with relevant ICD codes). During chart review, 78 ADEs were identified, with 19/40 (47.5%) from the subset with ICD codes. Of the 78 ADEs, 28.2%, 19.2%, and 7.7% were reported in ARTS, VA ADERS, and MedWatch, respectively.

CONCLUSION: We found substantial underreporting of apixaban and empagliflozin ADEs that became worse at each higher level of spontaneous reporting.

RevDate: 2020-06-04

Stöckl AL, O'Carroll DC, EJ Warrant (2020)

Hawkmoth lamina monopolar cells act as dynamic spatial filters to optimize vision at different light levels.

Science advances, 6(16):eaaz8645 pii:aaz8645.

How neural form and function are connected is a central question of neuroscience. One prominent functional hypothesis, from the beginnings of neuroanatomical study, states that laterally extending dendrites of insect lamina monopolar cells (LMCs) spatially integrate visual information. We provide the first direct functional evidence for this hypothesis using intracellular recordings from type II LMCs in the hawkmoth Macroglossum stellatarum. We show that their spatial receptive fields broaden with decreasing light intensities, thus trading spatial resolution for higher sensitivity. These dynamic changes in LMC spatial properties can be explained by the density and lateral extent of their dendritic arborizations. Our results thus provide the first physiological evidence for a century-old hypothesis, directly correlating physiological response properties with distinctive dendritic morphology.

RevDate: 2020-05-19

Scharf HM, Suarez AV, Reeve HK, et al (2020)

The evolution of conspecific acceptance threshold models.

Philosophical transactions of the Royal Society of London. Series B, Biological sciences, 375(1802):20190475.

How do organisms balance different types of recognition errors when cues associated with desirable and undesirable individuals or resources overlap? This is a fundamental question of signal detection theory (SDT). As applied in sociobiology, SDT is not limited to a single context or animal taxon, therefore its application can span what may be considered dissimilar systems. One of the applications of SDT is the suite of acceptance threshold models proposed by Reeve (1989), which analysed how individuals should balance acceptance and rejection errors in social discrimination decisions across a variety of recognition contexts, distinguished by how these costs and benefits relatively combine. We conducted a literature review to evaluate whether these models' specific predictions have been upheld. By examining over 350 research papers, we quantify how Reeve's models (Reeve 1989 Am. Nat.133, 407-435 (doi:10.1086/284926)) have influenced the field of ecological and behavioural recognition systems research. We found overall empirical support for the predictions of the specific models proposed by Reeve, and argue for further expansion of their applications into more diverse taxonomic and additional recognition contexts. This article is part of the theme issue 'Signal detection theory in recognition systems: from evolving models to experimental tests'.

RevDate: 2020-05-06

Hensgen R, England L, Homberg U, et al (2020)

Neuroarchitecture of the central complex in the brain of the honeybee: neuronal cell types.

The Journal of comparative neurology [Epub ahead of print].

The central complex (CX) in the insect brain is a higher order integration center that controls a number of behaviors, most prominently goal directed locomotion. The CX comprises the protocerebral bridge (PB), the upper division of the central body (CBU), the lower division of the central body (CBL), and the paired noduli (NO). Although spatial orientation has been extensively studied in honeybees at the behavioral level, most electrophysiological and anatomical analyses have been carried out in other insect species, leaving the morphology and physiology of neurons that constitute the CX in the honeybee mostly enigmatic. The goal of this study was to morphologically identify neuronal cell types of the CX in the honeybee Apis mellifera. By performing iontophoretic dye injections into the CX, we traced 16 subtypes of neuron that connect a subdivision of the CX with other regions in the bee`s central brain, and eight subtypes that mainly interconnect different subdivisions of the CX. They establish extensive connections between the CX and the lateral complex, the superior protocerebrum and the posterior protocerebrum. Characterized neuron classes and subtypes are morphologically similar to those described in other insects, suggesting considerable conservation in the neural network relevant for orientation.

RevDate: 2020-05-03

Noonan MJ, Fleming CH, Tucker MA, et al (2020)

Effects of body size on estimation of mammalian area requirements.

Conservation biology : the journal of the Society for Conservation Biology [Epub ahead of print].

Accurately quantifying species' area requirements is a prerequisite for effective area-based conservation. This typically involves collecting tracking data on species of interest and then conducting home-range analyses. Problematically, autocorrelation in tracking data can result in space needs being severely underestimated. Based on previous work, we hypothesized the magnitude of underestimation varies with body mass, a relationship that could have serious conservation implications. To evaluate this hypothesis for terrestrial mammals, we estimated home-range areas with GPS locations from 757 individuals across 61 globally distributed mammalian species with body masses ranging from 0.4 to 4,000 kg. We then applied block cross-validation to quantify bias in empirical home-range estimates. Area requirements of mammals <10 kg were underestimated by a mean ∼15%, and species weighing ∼100 kg were underestimated by ∼50% on average. Thus, we found area estimation was subject to autocorrelation-induced bias that was worse for large species. Combined with the fact that extinction risk increases as body mass increases, the allometric scaling of bias we observed suggests the most threatened species are also likely to be those with the least accurate home-range estimates. As a correction, we tested whether data thinning or autocorrelation-informed home-range estimation minimized the scaling effect of autocorrelation on area estimates. Data thinning required ankk ∼93% data loss to achieve statistical independence with 95% confidence and was therefore not a viable solution. In contrast, autocorrelation-informed home-range estimation resulted in consistently accurate estimates irrespective of mass. When relating body mass to home range size, we detected that correcting for autocorrelation resulted in a scaling exponent significantly >1, meaning the scaling of the relationship changed substantially at the upper end of the mass spectrum. Article impact statement: Due to autocorrelation-induced bias, conventional methods severely underestimate the area requirements of GPS-tracked large mammals. Efectos del Tamaño Corporal sobre la Estimación de los Requerimientos de Área de Mamíferos This article is protected by copyright. All rights reserved.

RevDate: 2020-04-30

Scheiner R, Frantzmann F, Jäger M, et al (2020)

A Novel Thermal-Visual Place Learning Paradigm for Honeybees (Apis mellifera).

Frontiers in behavioral neuroscience, 14:56.

Honeybees (Apis mellifera) have fascinating navigational skills and learning capabilities in the field. To decipher the mechanisms underlying place learning in honeybees, we need paradigms to study place learning of individual honeybees under controlled laboratory conditions. Here, we present a novel visual place learning arena for honeybees which relies on high temperatures as aversive stimuli. Honeybees learn to locate a safe spot in an unpleasantly warm arena, relying on a visual panorama. Bees can solve this task at a temperature of 46°C, while at temperatures above 48°C bees die quickly. This new paradigm, which is based on pioneering work on Drosophila, allows us now to investigate thermal-visual place learning of individual honeybees in the laboratory, for example after controlled genetic knockout or pharmacological intervention.

RevDate: 2020-04-27

Habenstein J, Amini E, Grübel K, et al (2020)

The brain of Cataglyphis ants: neuronal organization and visual projections.

The Journal of comparative neurology [Epub ahead of print].

Cataglyphis ants are known for their outstanding navigational abilities. They return to their inconspicuous nest after far-reaching foraging trips using path integration, and whenever available, learn and memorize visual features of panoramic sceneries. To achieve this, the ants combine directional visual information from celestial cues and panoramic scenes with distance information from an intrinsic odometer. The largely vision-based navigation in Cataglyphis requires sophisticated neuronal networks to process the broad repertoire of visual stimuli. Although Cataglyphis ants have been subject to many neuroethological studies, little is known about the general neuronal organization of their central brain and the visual pathways beyond major circuits. Here, we provide a comprehensive, three-dimensional neuronal map of synapse-rich neuropils in the brain of Cataglyphis nodus including major connecting fiber systems. In addition, we examined neuronal tracts underlying the processing of visual information in more detail. This study revealed a total of 33 brain neuropils and 30 neuronal fiber tracts including six distinct tracts between the optic lobes and the cerebrum. We also discuss the importance of comparative studies on insect brain architecture for a profound understanding of neuronal networks and their function. This article is protected by copyright. All rights reserved.

RevDate: 2020-04-24

Rudolph K, Fichtel C, Heistermann M, et al (2020)

Dynamics and determinants of glucocorticoid metabolite concentrations in wild Verreaux's sifakas.

Hormones and behavior pii:S0018-506X(20)30086-6 [Epub ahead of print].

Glucocorticoids have wide-ranging effects on animals' behaviour, but many of these effects remain poorly understood because numerous confounding factors have often been neglected in previous studies. Here, we present data from a 2-year study of 7 groups of wild Verreaux's sifakas (Propithecus verreauxi), in which we examined concentrations of faecal glucocorticoid metabolites (fGCMs, n = 2350 samples) simultaneously in relation to ambient temperatures, food intake, rank, reproduction, adult sex ratios, social interactions, vigilance and self-scratching. Multi-variate analyses revealed that fGCM concentrations were positively correlated with increases in daily temperature fluctuations and tended to decrease with increasing fruit intake. fGCM concentrations increased when males were sexually mature and began to disperse, and dominant males had higher fGCM concentrations than subordinate males. In contrast to males, older females showed a non-significant trend to have lower fGCM levels, potentially reflecting differences in male and female life-history strategies. Reproducing females had the highest fGCM concentrations during late gestation and had higher fGCM levels than non-reproducing females, except during early lactation. Variation in fGCM concentrations was not associated with variation in social interactions, adult sex ratios, vigilance and self-scratching. Altogether, we show that measures of glucocorticoid output constitute appropriate tools for studying energetic burdens of ecological and reproductive challenges. However, they seem to be insufficient indicators for immediate endocrinological responses to social and nonsocial behaviours that are not directly linked to energy metabolism.

RevDate: 2020-04-24

Grund-Mueller N, Ruedenauer FA, Spaethe J, et al (2020)

Adding Amino Acids to a Sucrose Diet Is Not Sufficient to Support Longevity of Adult Bumble Bees.

Insects, 11(4): pii:insects11040247.

Dietary macro-nutrients (i.e., carbohydrates, protein, and fat) are important for bee larval development and, thus, colony health and fitness. To which extent different diets (varying in macro-nutrient composition) affect adult bees and whether they can thrive on nectar as the sole amino acid source has, however, been little investigated. We investigated how diets varying in protein concentration and overall nutrient composition affected consumption, longevity, and breeding behavior of the buff-tailed bumble bee, Bombus terrestris (Hymenoptera: Apidae). Queenless micro-colonies were fed either natural nutrient sources (pollen), nearly pure protein (i.e., the milk protein casein), or sucrose solutions with low and with high essential amino acid content in concentrations as can be found in nectar. We observed micro-colonies for 110 days. We found that longevity was highest for pure pollen and lowest for pure sucrose solution and sucrose solution supplemented with amino acids in concentrations as found in the nectar of several plant species. Adding higher concentrations of amino acids to sucrose solution did only slightly increase longevity compared to sucrose alone. Consequently, sucrose solution with the applied concentrations and proportions of amino acids or other protein sources (e.g., casein) alone did not meet the nutritional needs of healthy adult bumble bees. In fact, longevity was highest and reproduction only successful in micro-colonies fed pollen. These results indicate that, in addition to carbohydrates and protein, adult bumble bees, like larvae, need further nutrients (e.g., lipids and micro-nutrients) for their well-being. An appropriate nutritional composition seemed to be best provided by floral pollen, suggesting that pollen is an essential dietary component not only for larvae but also for adult bees.

RevDate: 2020-03-28

Dolotovskaya S, Walker S, EW Heymann (2020)

What makes a pair bond in a Neotropical primate: female and male contributions.

Royal Society open science, 7(1):191489 pii:rsos191489.

Pair living and pair bonding are rare in mammals, and the mechanisms of their maintenance remain a puzzle. Titi monkeys, a 'textbook example' for 'monogamous' primates, have strong pair bonds and extensive male care. To investigate mechanisms of pair-bond maintenance, we studied seven wild groups of red titis (Plecturocebus cupreus) in Peruvian Amazonia over a period of 14 months. We analysed pair bonds by measuring proximity, grooming and approaches/leaves within pairs, and collected data on intergroup encounters. Females contributed to grooming more than males, especially during infant dependency, when most of the grooming within pairs was done by females. Females were also more active in controlling proximity between pair mates, making most of the approaches and leaves. Males, on the other hand, invested more in territorial defences. They participated in more intergroup encounters than females and were more active during these encounters. Our data is most consistent with the 'male-services' hypothesis for pair-bond maintenance, where a female contributes more to the proximity and affiliation maintenance while a male provides beneficial services.

RevDate: 2020-03-11

Secor PR, AA Dandekar (2020)

More than Simple Parasites: the Sociobiology of Bacteriophages and Their Bacterial Hosts.

mBio, 11(2): pii:mBio.00041-20.

Bacteria harbor viruses called bacteriophages that, like all viruses, co-opt the host cellular machinery to replicate. Although this relationship is at first glance parasitic, there are social interactions among and between bacteriophages and their bacterial hosts. These social interactions can take on many forms, including cooperation, altruism, and cheating. Such behaviors among individuals in groups of bacteria have been well described. However, the social nature of some interactions between phages or phages and bacteria is only now becoming clear. We are just beginning to understand how bacteriophages affect the sociobiology of bacteria, and we know even less about social interactions within bacteriophage populations. In this review, we discuss recent developments in our understanding of bacteriophage sociobiology, including how selective pressures influence the outcomes of social interactions between populations of bacteria and bacteriophages. We also explore how tripartite social interactions between bacteria, bacteriophages, and an animal host affect host-microbe interactions. Finally, we argue that understanding the sociobiology of bacteriophages will have implications for the therapeutic use of bacteriophages to treat bacterial infections.

RevDate: 2020-02-28

Dolotovskaya S, Flores Amasifuen C, Haas CE, et al (2019)

Active anti-predator behaviour of red titi monkeys (Plecturocebus cupreus).

Primate biology, 6(1):59-64 pii:01021829.

Due to their inconspicuous behaviour and colouration, it has been assumed that titi monkeys' main anti-predator behaviour is passive crypsis and hiding. So far, active predator mobbing has been documented only for black-fronted titi monkeys, Callicebusnigrifrons. Here we report for the first time mobbing behaviour of red titi monkeys, Plecturocebus cupreus (previously Callicebus cupreus), as reaction to an ocelot (Leopardus pardalis) and a Boa constrictor. We also report other active anti-predator behaviours, such as alarm calling and approaching, as reactions to tayras (Eira barbara) and raptors. Our observations provide additional evidence for sex differences in anti-predator behaviour, possibly related to the evolution and maintenance of social monogamy.

RevDate: 2020-02-27

Cosarinsky MI, Römer D, F Roces (2020)

Nest Turrets of Acromyrmex Grass-Cutting Ants: Micromorphology Reveals Building Techniques and Construction Dynamics.

Insects, 11(2): pii:insects11020140.

Acromyrmex fracticornis grass-cutting ants construct conspicuous chimney-shaped nest turrets made of intermeshed grass fragments. We asked whether turrets are constructed by merely piling up nearby materials around the entrance, or whether ants incorporate different materials as the turret develops. By removing the original nest turrets and following their rebuilding process over three consecutive days, age-dependent changes in wall morphology and inner lining fabrics were characterized. Micromorphological descriptions based on thin sections of turret walls revealed the building behaviors involved. Ants started by collecting nearby twigs and dry grass fragments that are piled up around the nest entrance. Several large fragments held the structure like beams. As a net-like structure grew, soil pellets were placed in between the intermeshed plant fragments from the turret base to the top, reinforcing the structure. Concomitantly, the turret inner wall was lined with soil pellets, starting from the base. Therefore, the consolidation of the turret occurred both over time and from its base upwards. It is argued that nest turrets do not simply arise by the arbitrary deposition of nearby materials, and that workers selectively incorporate large materials at the beginning, and respond to the developing structure by reinforcing the intermeshed plant fragments over time.

RevDate: 2020-02-25

Poirotte C, MJE Charpentier (2020)

Unconditional care from close maternal kin in the face of parasites.

Biology letters, 16(2):20190869.

Several species mitigate relationships according to their conspecifics' parasite status. Yet, this defence strategy comes with the costs of depriving individuals from valuable social bonds. Animals therefore face a trade-off between the costs of pathogen exposure and the benefits of social relationships. According to the models of social evolution, social bonds are highly kin-biased. However, whether kinship mitigates social avoidance of contagious individuals has never been tested so far. Here, we build on previous research to demonstrate that mandrills (Mandrillus sphinx) modulate social avoidance of contagious individuals according to kinship: individuals do not avoid grooming their close maternal kin when contagious (parasitized with oro-faecally transmitted protozoa), although they do for more distant or non-kin. While individuals' parasite status has seldom been considered as a trait impacting social relationships in animals, this study goes a step beyond by showing that kinship balances the effect of health status on social behaviour in a non-human primate.

RevDate: 2020-02-17

Kappeler PM, L Pozzi (2019)

Evolutionary transitions toward pair living in nonhuman primates as stepping stones toward more complex societies.

Science advances, 5(12):eaay1276 pii:aay1276.

Nonhuman primate societies vary tremendously in size and composition, but how and why evolutionary transitions among different states occurred remains highly controversial. In particular, how many times pair living evolved and the social states of the ancestors of pair- and group-living species remains contentious. We examined evolutionary transitions in primate social evolution by using new, independent categorizations of sociality and different phylogenetic hypotheses with a vastly expanded dataset. Using Bayesian phylogenetic comparative methods, we consistently found the strongest support for a model that invokes frequent transitions between solitary ancestors and pair-living descendants, with the latter giving rise to group-living species. This result was robust to systematic variation in social classification, sample size, and phylogeny. Our analyses therefore indicate that pair living was a stepping stone in the evolution of structurally more complex primate societies, a result that bolsters the role of kin selection in social evolution.

RevDate: 2020-02-07

Gutmann DH (2020)

The Sociobiology of Brain Tumors.

Advances in experimental medicine and biology, 1225:115-125.

Brain tumors are complex cellular ecosystems, composed of populations of both neoplastic and non-neoplastic cell types. While the contributions of the cancer cells in low-grade and high-grade gliomas have been extensively studied, there is comparatively less known about the contributions of the non-neoplastic cells in these tumors. As such, a large proportion of the non-neoplastic cells in gliomas are resident brain microglia, infiltrating circulating macrophages, and T lymphocytes. These immune system-like stromal cells are recruited into the evolving tumor through the elaboration of chemokines, and are reprogrammed to adopt new cellular identities critical for glioma formation, maintenance, and progression. In this manner, these populations of tumor-associated microglia and macrophages produce growth factors that support gliomagenesis and continued tumor growth. As we begin to characterize these immune cell contributions, future therapies might emerge as adjuvant approaches to glioma treatment.

RevDate: 2020-02-06

Dore KM, Hansen MF, Klegarth AR, et al (2020)

Correction to: Review of GPS collar deployments and performance on nonhuman primates.

In the original publication of the article, figure 1 was wrongly published as a duplication.

RevDate: 2020-02-06

Darling Rasmussen P, OJ Storebø (2020)

Attachment and Epigenetics: A Scoping Review of Recent Research and Current Knowledge.

Psychological reports [Epub ahead of print].

RevDate: 2020-02-04

Prox L, D Farine (2020)

A framework for conceptualizing dimensions of social organization in mammals.

Ecology and evolution, 10(2):791-807 pii:ECE35936.

Mammalian societies represent many different types of social systems. While some aspects of social systems have been extensively studied, there is little consensus on how to conceptualize social organization across species. Here, we present a framework describing eight dimensions of social organization to capture its diversity across mammalian societies. The framework uses simple information that is clearly separated from the three other aspects of social systems: social structure, care system, and mating system. By applying our framework across 208 species of all mammalian taxa, we find a rich multidimensional landscape of social organization. Correlation analysis reveals that the dimensions have relatively high independence, suggesting that social systems are able to evolve different aspects of social behavior without being tied to particular traits. Applying a clustering algorithm allows us to identify the relative importance of key dimensions on patterns of social organization. Finally, mapping mating system onto these clusters shows that social organization represents a distinct aspect of social systems. In the future, this framework will aid reporting on important aspects of natural history in species and facilitate comparative analyses, which ultimately will provide the ability to generate new insights into the primary drivers of social patterns and evolution of sociality.

RevDate: 2020-01-30
CmpDate: 2020-01-30

Pernu TK, H Helantera (2019)

Genetic relatedness and its causal role in the evolution of insect societies.

Journal of biosciences, 44(4):.

The role of genetic relatedness in social evolution has recently come under critical attention. These arguments are here critically analyzed, both theoretically and empirically. It is argued that when the conceptual structure of the theory of natural selection is carefully taken into account, genetic relatedness can be seen to play an indispensable role in the evolution of both facultative and advanced eusociality. Although reviewing the empirical evidence concerning the evolution of eusociality reveals that relatedness does not play a role in the initial appearance of helper phenotypes, this follows simply from the fact that natural selection - of which relatedness is a necessary component - does not play a causal role in the origin of any traits. Further, separating two logically distinct elements of causal explanation - necessity and sufficiency - explains why the debate lingers on: although relatedness plays a necessary role in the evolution of helping and advanced eusociality, relatedness alone is not sufficient for their appearance. Therefore, if the relatedness variable in a given data set is held at a uniformly high value, then it indeed may turn out that other factors occupy a more prominent role. However, this does not change the fact that high relatedness functions as a necessary background condition for the evolution of advanced eusociality.

RevDate: 2020-01-22

Dore KM, Hansen MF, Klegarth AR, et al (2020)

Review of GPS collar deployments and performance on nonhuman primates.

Primates; journal of primatology pii:10.1007/s10329-020-00793-7 [Epub ahead of print].

Over the past 20 years, GPS collars have emerged as powerful tools for the study of nonhuman primate (hereafter, "primate") movement ecology. As the size and cost of GPS collars have decreased and performance has improved, it is timely to review the use and success of GPS collar deployments on primates to date. Here we compile data on deployments and performance of GPS collars by brand and examine how these relate to characteristics of the primate species and field contexts in which they were deployed. The compiled results of 179 GPS collar deployments across 17 species by 16 research teams show these technologies can provide advantages, particularly in adding to the quality, quantity, and temporal span of data collection. However, aspects of this technology still require substantial improvement in order to make deployment on many primate species pragmatic economically. In particular, current limitations regarding battery lifespan relative to collar weight, the efficacy of remote drop-off mechanisms, and the ability to remotely retrieve data need to be addressed before the technology is likely to be widely adopted. Moreover, despite the increasing utility of GPS collars in the field, they remain substantially more expensive than VHF collars and tracking via handheld GPS units, and cost considerations of GPS collars may limit sample sizes and thereby the strength of inferences. Still, the overall high quality and quantity of data obtained, combined with the reduced need for on-the-ground tracking by field personnel, may help defray the high equipment cost. We argue that primatologists armed with the information in this review have much to gain from the recent, substantial improvements in GPS collar technology.

RevDate: 2020-01-18

Szabo B, MJ Whiting (2020)

Do lizards have enhanced inhibition? A test in two species differing in ecology and sociobiology.

Behavioural processes pii:S0376-6357(19)30394-8 [Epub ahead of print].

Waiting for the right moment to strike, avoiding the ingestion of harmful foods, or ignoring stimuli associated with ephemeral or depleted resources requires the inhibition of prepotent responses. Good response inhibition facilities flexibility in behaviour which is associated with survival in unpredictable environments. To investigate differences in behavioural flexibility in lizards, we tested reversal learning in the sleepy lizard (Tiliqua rugosa asper) and compared its performance to the relatively closely related eastern blue-tongue skink (Tiliqua scincoides scincoides). We presented both species with a choice between either a light and dark blue stimulus or a triangle and X shape. Both species were able to learn to discriminate between these stimuli and showed similar learning ability during the acquisition of the discrimination. Sleepy lizards, however, demonstrated a higher probability of making a correct choice at the start of the reversal, hinting towards enhanced stimulus response inhibition. Sleepy lizards and blue-tongue skinks inhabit different environments and show differences in ecology and sociobiology, all of which could possibly lead to adaptive specialisation in cognitive ability. Although further research is required, we propose that selection might have led to a change in stimulus response inhibition in the arid-adapted sleepy lizard, because better response inhibition might help them avoid the costs of repeated choices to unpredictable environmental stimuli.

RevDate: 2020-01-16

Ruedenauer FA, Raubenheimer D, Kessner-Beierlein D, et al (2020)

Best be(e) on low fat: linking nutrient perception, regulation and fitness.

Ecology letters [Epub ahead of print].

Preventing malnutrition through consuming nutritionally appropriate resources represents a challenge for foraging animals. This is due to often high variation in the nutritional quality of available resources. Foragers consequently need to evaluate different food sources. However, even the same food source can provide a plethora of nutritional and non-nutritional cues, which could serve for quality assessment. We show that bumblebees, Bombus terrestris, overcome this challenge by relying on lipids as nutritional cue when selecting pollen. The bees 'prioritised' lipid perception in learning experiments and avoided lipid consumption in feeding experiments, which supported survival and reproduction. In contrast, survival and reproduction were severely reduced by increased lipid contents. Our study highlights the importance of fat regulation for pollen foraging bumblebees. It also reveals that nutrient perception, nutrient regulation and reproductive fitness can be linked, which represents an effective strategy enabling quick foraging decisions that prevent malnutrition and maximise fitness.

RevDate: 2020-01-15

Groh C, W Rössler (2020)

Analysis of Synaptic Microcircuits in the Mushroom Bodies of the Honeybee.

Insects, 11(1): pii:insects11010043.

Mushroom bodies (MBs) are multisensory integration centers in the insect brain involved in learning and memory formation. In the honeybee, the main sensory input region (calyx) of MBs is comparatively large and receives input from mainly olfactory and visual senses, but also from gustatory/tactile modalities. Behavioral plasticity following differential brood care, changes in sensory exposure or the formation of associative long-term memory (LTM) was shown to be associated with structural plasticity in synaptic microcircuits (microglomeruli) within olfactory and visual compartments of the MB calyx. In the same line, physiological studies have demonstrated that MB-calyx microcircuits change response properties after associative learning. The aim of this review is to provide an update and synthesis of recent research on the plasticity of microcircuits in the MB calyx of the honeybee, specifically looking at the synaptic connectivity between sensory projection neurons (PNs) and MB intrinsic neurons (Kenyon cells). We focus on the honeybee as a favorable experimental insect for studying neuronal mechanisms underlying complex social behavior, but also compare it with other insect species for certain aspects. This review concludes by highlighting open questions and promising routes for future research aimed at understanding the causal relationships between neuronal and behavioral plasticity in this charismatic social insect.

RevDate: 2020-01-06

Ernst UR (2020)

Digest: Evolution of eusociality favored by split sex ratios under worker-control.

Evolution; international journal of organic evolution, 74(1):201-202.

Eusociality has repeatedly independently evolved in ants, bees, and wasps (Hymenoptera), leading to the idea that haplodiploidy may be an important driving factor in this group. Using a modeling approach, Quiñones et al. show that split sex ratios and worker control of sex ratios (achieved by removal of male brood) can promote the initial evolution of helping raise offspring of related individuals. However, over time, these factors can result in social polymorphism, that is, a mix of solitary and social nests, or to eusocial colonies with three different strategies, namely those that produce mostly females, mostly males, or a balanced sex ratio.

RevDate: 2020-01-15

Shell WA, SM Rehan (2019)

Social modularity: conserved genes and regulatory elements underlie caste-antecedent behavioural states in an incipiently social bee.

Proceedings. Biological sciences, 286(1916):20191815.

The evolutionary origins of advanced eusociality, one of the most complex forms of phenotypic plasticity in nature, have long been a focus within the field of sociobiology. Although eusocial insects are known to have evolved from solitary ancestors, sociogenomic research among incipiently social taxa has only recently provided empirical evidence supporting theories that modular regulation and deeply conserved genes may play important roles in both the evolutionary emergence and elaboration of insect sociality. There remains, however, a paucity of data to further test the biological reality of these and other evolutionary theories among taxa in the earliest stages of social evolution. Here, we present brain transcriptomic data from the incipiently social small carpenter bee, Ceratina calcarata, which captures patterns of cis-regulation and gene expression associated with female maturation, and underlying two well-defined behavioural states, foraging and guarding, concurrently demonstrated by mothers and daughters during early autumn. We find that an incipiently social nest environment may dramatically affect gene expression. We further reveal foraging and guarding behaviours to be putatively caste-antecedent states in C. calcarata, and offer strong empirical support for the operation of modular regulation, involving deeply conserved and differentially expressed genes in the expression of early social forms.

RevDate: 2020-01-08

Cordoni G, E Palagi (2019)

Back to the Future: A Glance Over Wolf Social Behavior to Understand Dog-Human Relationship.

Animals : an open access journal from MDPI, 9(11):.

This review focuses on wolf sociobiology to delineate the traits of cooperative baggage driven by natural selection (wolf-wolf cooperation) and better understand the changes obtained by artificial selection (dog-human cooperation). We selected some behaviors of the dog's ancestors that provide the basis for the expression of a cooperative society, such as dominance relationships, leverage power, post-aggressive strategies, and playful dynamics between pack members. When possible, we tried to compare the data on wolves with those coming from the dog literature. Wolves can negotiate commodities when the interacting subjects occupy different ranking positions by bargaining social tolerance with helping and support. They are able to manage group disruption by engaging in sophisticated post-conflict maneuvers, thus restoring the relationship between the opponents and reducing the spreading of aggression in the group. Wolves engage in social play also as adults to manipulate social relationships. They are able to flexibly adjust their playful interactions to minimize the risk of escalation. Complex cognitive abilities and communicative skills are probably the main proximate causes for the evolution of inter-specific cooperation in wolves.

RevDate: 2020-01-08

Zinner D, Groeneveld LF, Keller C, et al (2019)

Correction to: Mitochondrial phylogeography of baboons (Papio spp.) - Indication for introgressive hybridization?.

BMC evolutionary biology, 19(1):198.

Following publication of the original article [1], we have been notified that some of the NCB accession numbers were incorrectly associated to their corresponding taxon in the Additional file 1.

RevDate: 2019-11-03

Fortunato A, A Aktipis (2019)

Social feeding behavior of Trichoplax adhaerens.

Frontiers in ecology and evolution, 7:.

Animals have evolved different foraging strategies in which some animals forage independently and others forage in groups. The evolution of social feeding does not necessarily require cooperation; social feeding can be a beneficial individual-level strategy if it provides mutualistic benefits, for example though increasing the efficiency of resource extraction or processing. We found that Trichoplax adhaerens, the simplest multicellular animal ever described, engages in social feeding behavior. T. adhaerens lacks muscle tissue, nervous and digestive systems - yet is capable of aggregating and forming groups of closely connected individuals who collectively feed. The tight physical interactions between the animals are transitory and appear to serve the goal of staying connected to neighbors during the external digestion of algae when enzymes are released on the biofilm and nutrients are absorbed through the ventral epithelium. We found that T. adhaerens are more likely to engage in social feeding when the concentrations of algae are high - both in a semi-natural conditions and in vitro. It is surprising that T. adhaerens - an organism without a nervous system - is able to engage in this social feeding behavior. Whether this behavior is cooperative is still an open question. Nevertheless, the social feeding behavior of T. adhaerens, an early multicellular animal, suggests that sociality may have played an important role in the early evolution of animals. It also suggests that T. adhaerens could be used as a simple model organism for exploring questions regarding ecology and sociobiology.

RevDate: 2019-11-03

Eckhardt F, Strube C, Mathes KA, et al (2019)

Parasite burden in a short-lived chameleon, Furcifer labordi.

International journal for parasitology. Parasites and wildlife, 10:231-240.

Life history theory predicts that species with shorter lifespan should show higher investments into growth and reproduction at the expense of immune defenses. Labord's chameleon (Furcifer labordi) is the tetrapod with the shortest known life span. To investigate to which extent immunosenescence influences the die-off of these chameleons when they are only about 6 months old, we examined the gastrointestinal-, blood- and ectoparasite burden in F. labordi in Kirindy Forest (western Madagascar) and compared them with sympatric and longer living F. cf. nicosiai. Moreover, we included data from wild F. labordi that were singly housed under ambient conditions with daily food and water supply. Gastrointestinal parasite prevalence of wild F. labordi increased dramatically during the last 3 months of their lives, which include the reproductive period. Furcifer cf. nicosiai was found to have a belated increase in gastrointestinal parasites compared to F. labordi. In F. cf. nicosiai higher prevalence of blood parasites were found, which probably result from the longer exposure to the arthropod intermediate host. Both species showed infestations with ectoparasites, which peaked in the rainy season but disappeared towards the dry season. Male F. labordi showed a significantly higher prevalence of gastrointestinal - and ectoparasites and higher intensities of coccidians and ectoparasites than females. Males of F. cf. nicosiai exhibited higher prevalence of blood- and ectoparasites, as well as higher intensities in ectoparasites. Caged individuals of both sexes showed delayed senescence, reduced parasite burden and lived longer than their wild conspecifics. Overall, the increase in the prevalence in gastrointestinal - and blood parasites towards the disappearance of the wild population of F. labordi indicates that this species invests comparatively less energy in efficient immune system function, supporting the prediction of life history theory.

RevDate: 2019-10-23

Nonacs P (2019)

Reproductive skew in cooperative breeding: Environmental variability, antagonistic selection, choice, and control.

Ecology and evolution, 9(18):10163-10175.

A multitude of factors may determine reproductive skew among cooperative breeders. One explanation, derived from inclusive fitness theory, is that groups can partition reproduction such that subordinates do at least as well as noncooperative solitary individuals. The majority of recent data, however, fails to support this prediction; possibly because inclusive fitness models cannot easily incorporate multiple factors simultaneously to predict skew. Notable omissions are antagonistic selection (across generations, genes will be in both dominant and subordinate bodies), constraints on the number of sites suitable for successful reproduction, choice in which group an individual might join, and within-group control or suppression of competition. All of these factors and more are explored through agent-based evolutionary simulations. The results suggest the primary drivers for the initial evolution of cooperative breeding may be a combination of limited suitable sites, choice across those sites, and parental manipulation of offspring into helping roles. Antagonistic selection may be important when subordinates are more frequent than dominants. Kinship matters, but its main effect may be in offspring being available for manipulation while unrelated individuals are not. The greater flexibility of evolutionary simulations allows the incorporation of species-specific life histories and ecological constraints to better predict sociobiology.

RevDate: 2020-01-08

Defolie C, Merkling T, C Fichtel (2019)

Patterns and variation in the mammal parasite-glucocorticoid relationship.

Biological reviews of the Cambridge Philosophical Society [Epub ahead of print].

Parasites are ubiquitous and can strongly affect their hosts through mechanisms such as behavioural changes, increased energetic costs and/or immunomodulation. When parasites are detrimental to their hosts, they should act as physiological stressors and elicit the release of glucocorticoids. Alternatively, previously elevated glucocorticoid levels could facilitate parasite infection due to neuroimmunomodulation. However, results are equivocal, with studies showing either positive, negative or no relationship between parasite infection and glucocorticoid levels. Since factors such as parasite type, infection severity or host age and sex can influence the parasite-glucocorticoid relationship, we review the main mechanisms driving this relationship. We then perform a phylogenetic meta-analysis of 110 records from 65 studies in mammalian hosts from experimental and observational studies to quantify the general direction of this relationship and to identify ecological and methodological drivers of the observed variability. Our review produced equivocal results concerning the direction of the relationship, but there was stronger support for a positive relationship, although causality remained unclear. Mechanisms such as host manipulation for parasite survival, host response to infection, cumulative effects of multiple stressors, and neuro-immunomodulatory effects of glucocorticoids could explain the positive relationship. Our meta-analysis results revealed an overall positive relationship between glucocorticoids and parasitism among both experimental and observational studies. Because all experimental studies included were parasite manipulations, we conclude that parasites caused in general an increase in glucocorticoid levels. To obtain a better understanding of the directionality of this link, experimental manipulation of glucocorticoid levels is now required to assess the causal effects of high glucocorticoid levels on parasite infection. Neither parasite type, the method used to assess parasite infection nor phylogeny influenced the relationship, and there was no evidence for publication bias. Future studies should attempt to be as comprehensive as possible, including moderators potentially influencing the parasite-glucocorticoid relationship. We particularly emphasise the importance of testing hosts of a broad age range, concomitantly measuring sex hormone levels or at least reproductive status, and for observational studies, also considering food availability, host body condition and social stressors to obtain a better understanding of the parasite-glucocorticoid relationship.

RevDate: 2020-01-03

Gogarten JF, Calvignac-Spencer S, Nunn CL, et al (2020)

Metabarcoding of eukaryotic parasite communities describes diverse parasite assemblages spanning the primate phylogeny.

Molecular ecology resources, 20(1):204-215.

Despite their ubiquity, in most cases little is known about the impact of eukaryotic parasites on their mammalian hosts. Comparative approaches provide a powerful method to investigate the impact of parasites on host ecology and evolution, though two issues are critical for such efforts: controlling for variation in methods of identifying parasites and incorporating heterogeneity in sampling effort across host species. To address these issues, there is a need for standardized methods to catalogue eukaryotic parasite diversity across broad phylogenetic host ranges. We demonstrate the feasibility of a metabarcoding approach for describing parasite communities by analysing faecal samples from 11 nonhuman primate species representing divergent lineages of the primate phylogeny and the full range of sampling effort (i.e. from no parasites reported in the literature to the best-studied primates). We detected a number of parasite families and regardless of prior sampling effort, metabarcoding of only ten faecal samples identified parasite families previously undescribed in each host (x̅ = 8.5 new families per species). We found more overlap between parasite families detected with metabarcoding and published literature when more research effort-measured as the number of publications-had been conducted on the host species' parasites. More closely related primates and those from the same continent had more similar parasite communities, highlighting the biological relevance of sampling even a small number of hosts. Collectively, results demonstrate that metabarcoding methods are sensitive and powerful enough to standardize studies of eukaryotic parasite communities across host species, providing essential new tools for macroecological studies of parasitism.

RevDate: 2019-10-27

Gadenne C, Groh C, Grübel K, et al (2019)

Neuroanatomical correlates of mobility: Sensory brain centres are bigger in winged than in wingless parthenogenetic pea aphid females.

Arthropod structure & development, 52:100883.

Many aphid species reproduce parthenogenetically throughout most of the year, with individuals having identical genomes. Nevertheless, aphid clones display a marked polyphenism with associated behavioural differences. Pea aphids (Acyrthosiphon pisum), when crowded, produce winged individuals, which have a larger dispersal range than wingless individuals. We examined here if brain structures linked to primary sensory processing and high-order motor control change in size as a function of wing polyphenism. Using micro-computing tomography (micro-CT) scans and immunocytochemical staining with anti-synapsin antibody, we reconstructed primary visual (optic lobes) and olfactory (antennal lobes) neuropils, together with the central body of winged and wingless parthenogenetic females of A. pisum for volume measurements. Absolute neuropil volumes were generally bigger in anti-synapsin labelled brains compared to micro-CT scans. This is potentially due to differences in rearing conditions of the used aphids. Independent of the method used, however, winged females consistently had larger antennal lobes and optic lobes than wingless females in spite of a larger overall body size of wingless compared to winged females. The volume of the central body, on the other hand was not significantly different between the two morphs. The larger primary sensory centres in winged aphids might thus provide the neuronal substrate for processing different environmental information due to the increased mobility during flight.

RevDate: 2019-11-15
CmpDate: 2019-10-08

Bentz C, Dediu D, Verkerk A, et al (2018)

The evolution of language families is shaped by the environment beyond neutral drift.

Nature human behaviour, 2(11):816-821.

There are more than 7,000 languages spoken in the world today1. It has been argued that the natural and social environment of languages drives this diversity2-13. However, a fundamental question is how strong are environmental pressures, and does neutral drift suffice as a mechanism to explain diversification? We estimate the phylogenetic signals of geographic dimensions, distance to water, climate and population size on more than 6,000 phylogenetic trees of 46 language families. Phylogenetic signals of environmental factors are generally stronger than expected under the null hypothesis of no relationship with the shape of family trees. Importantly, they are also-in most cases-not compatible with neutral drift models of constant-rate change across the family tree branches. Our results suggest that language diversification is driven by further adaptive and non-adaptive pressures. Language diversity cannot be understood without modelling the pressures that physical, ecological and social factors exert on language users in different environments across the globe.

RevDate: 2019-11-15
CmpDate: 2019-10-08

San Martin A, Sinaceur M, Madi A, et al (2018)

Self-assertive interdependence in Arab culture.

Nature human behaviour, 2(11):830-837.

Arabs represent a major cultural group, yet one that is relatively neglected in cultural psychology. We hypothesized that Arab culture is characterized by a unique form of interdependence that is self-assertive. Arab cultural identity emerged historically in regions with harsh ecological and climatic environments, in which it was necessary to protect the survival of tribal groups. Individuals in Arabian cultures were honour-bound to be respectable and trustworthy group members. Supporting this hypothesis, study 1 found that Arabs were interdependent and holistic (like East Asians), but also self-assertive (like Westerners). This psychological profile was observed equally for both Muslim and Christian Arabs, thus ruling out Islamic religion as an alternative explanation for our findings. Studies 2 and 3 showed that the self-assertive tendency of Arabs is in service of interdependence, whereas that of Westerners is in service of independence. Our work contributes to the current effort by cultural psychologists to go beyond the prevailing East versus West, interdependence versus independence paradigm. It also speaks to the emerging socioecological perspective in cultural research.

RevDate: 2020-01-08

Peckre LR, Lowie A, Brewer D, et al (2019)

Food mobility and the evolution of grasping behaviour: a case study in strepsirrhine primates.

The Journal of experimental biology, 222(Pt 20): pii:jeb.207688.

Manual grasping is widespread among tetrapods but is more prominent and dexterous in primates. Whether the selective pressures that drove the evolution of dexterous hand grasping involved the collection of fruit or predation on mobile insects remains an area of debate. One way to explore this question is to examine preferences for manual versus oral grasping of a moving object. Previous studies on strepsirrhines have shown a preference for oral grasping when grasping static food items and a preference for manual grasping when grasping mobile prey such as insects, but little is known about the factors at play. Using a controlled experiment with a simple and predictable motion of a food item, we tested and compared the grasping behaviours of 53 captive individuals belonging to 17 species of strepsirrhines while grasping swinging food items and static food items. The swinging motion increased the frequency of hand-use for all individuals. Our results provide evidence that the swinging motion of the food is a sufficient parameter to increase hand grasping in a wide variety of strepsirrhine primates. From an evolutionary perspective, this result gives some support to the idea that hand-grasping abilities evolved under selective pressure associated with the predation of food items in motion. Looking at a common grasping pattern across a large set of species, this study provides important insight into comparative approaches to understanding the evolution of the hand grasping of food in primates and potentially other tetrapod taxa.

RevDate: 2020-01-11

Hunnicutt KE, Tiley GP, Williams RC, et al (2020)

Comparative Genomic Analysis of the Pheromone Receptor Class 1 Family (V1R) Reveals Extreme Complexity in Mouse Lemurs (Genus, Microcebus) and a Chromosomal Hotspot across Mammals.

Genome biology and evolution, 12(1):3562-3579.

Sensory gene families are of special interest for both what they can tell us about molecular evolution and what they imply as mediators of social communication. The vomeronasal type-1 receptors (V1Rs) have often been hypothesized as playing a fundamental role in driving or maintaining species boundaries given their likely function as mediators of intraspecific mate choice, particularly in nocturnal mammals. Here, we employ a comparative genomic approach for revealing patterns of V1R evolution within primates, with a special focus on the small-bodied nocturnal mouse and dwarf lemurs of Madagascar (genera Microcebus and Cheirogaleus, respectively). By doubling the existing genomic resources for strepsirrhine primates (i.e. the lemurs and lorises), we find that the highly speciose and morphologically cryptic mouse lemurs have experienced an elaborate proliferation of V1Rs that we argue is functionally related to their capacity for rapid lineage diversification. Contrary to a previous study that found equivalent degrees of V1R diversity in diurnal and nocturnal lemurs, our study finds a strong correlation between nocturnality and V1R elaboration, with nocturnal lemurs showing elaborate V1R repertoires and diurnal lemurs showing less diverse repertoires. Recognized subfamilies among V1Rs show unique signatures of diversifying positive selection, as might be expected if they have each evolved to respond to specific stimuli. Furthermore, a detailed syntenic comparison of mouse lemurs with mouse (genus Mus) and other mammalian outgroups shows that orthologous mammalian subfamilies, predicted to be of ancient origin, tend to cluster in a densely populated region across syntenic chromosomes that we refer to as a V1R "hotspot."

RevDate: 2020-01-08

Savage DA (2019)

Towards a complex model of disaster behaviour.

Disasters, 43(4):771-798.

This paper outlines why a move towards a complex adaptive systems model of behaviour is required if the goal is to generate better understanding of how individuals and groups interact with their environment in a disaster setting. To accomplish this objective, a bridge must be built between the broader social sciences and behavioural economics to incorporate discipline-specific insights that are needed to move towards complexity. This is only possible through a deeper understanding of behaviour and how the environment in which they occur can influence actions. It is then that one can counteract the poor behavioural predictions, flawed policies based on myth, inefficient design, and suboptimal outcomes that have flourished in the absence of a complex adaptive systems model. This paper provides a conceptual framework that draws on concepts from across the natural and social sciences, such as behavioural economics, endocrinology, psychology, sociobiology, and sociology in order to build an interactive theory of disaster behaviour.

RevDate: 2019-10-10
CmpDate: 2019-10-09

Ruedenauer FA, Spaethe J, van der Kooi CJ, et al (2019)

Pollinator or pedigree: which factors determine the evolution of pollen nutrients?.

Oecologia, 191(2):349-358.

A prime example of plant-animal interactions is the interaction between plants and pollinators, which typically receive nectar and/or pollen as reward for their pollination service. While nectar provides mostly carbohydrates, pollen represents the main source of protein and lipids for many pollinators. However, the main function of pollen is to carry nutrients for pollen tube growth and thus fertilization. It is unclear whether pollinator attraction exerts a sufficiently strong selective pressure to alter the nutritional profile of pollen, e.g., through increasing its crude protein content or protein-to-lipid ratio, which both strongly affect bee foraging. Pollen nutritional quality may also be merely determined by phylogenetic relatedness, with pollen of closely related plants showing similar nutritional profiles due to shared biosynthetic pathways or floral morphologies. Here, we present a meta-analysis of studies on pollen nutrients to test whether differences in pollen nutrient contents and ratios correlated with plant insect pollinator dependence and/or phylogenetic relatedness. We hypothesized that if pollen nutritional content was affected by pollinator attraction, it should be different (e.g., higher) in highly pollinator-dependent plants, independent of phylogenetic relatedness. We found that crude protein and the protein-to-lipid ratio in pollen strongly correlated with phylogeny. Moreover, pollen protein content was higher in plants depending mostly or exclusively on insect pollination. Pollen nutritional quality thus correlated with both phylogenetic relatedness and pollinator dependency, indicating that, besides producing pollen with sufficient nutrients for reproduction, the nutrient profile of zoophilous plants may have been shaped by their pollinators' nutritional needs.

RevDate: 2020-01-14

Poirotte C, PM Kappeler (2019)

Hygienic personalities in wild grey mouse lemurs vary adaptively with sex.

Proceedings. Biological sciences, 286(1908):20190863.

Detecting the risk of infection and minimizing parasite exposure represent the first lines of host defence against parasites. Individuals differ in the expression of these behavioural defences, but causes of such variation have received little empirical attention. We therefore experimentally investigated the effects of several individual and environmental factors on the expression level of faecal avoidance in the context of feeding, drinking, sleeping and defecating in a wild primate population. We found a strong sex bias in the expression level of anti-parasite behaviours of grey mouse lemurs (Microcebus murinus), with only females strongly avoiding contaminated food, water and nests, and exhibiting selective defecation. Our results further suggest that individuals adapted their protective behaviours according to variation in intrinsic and ecological factors that may influence the cost-benefit balance of behavioural defences. Overall, individuals exhibited high consistency of investment in protective behaviours across behavioural contexts and time, suggesting that grey mouse lemurs exhibit different hygienic personalities. Finally, the global hygienic score was negatively correlated with faecal-orally transmitted parasite richness, suggesting that variation in behavioural defence has fitness consequences. We suggest that integrating inter-individual variation in behavioural defences in epidemiological studies should improve our ability to model disease spread within populations.

RevDate: 2019-12-17
CmpDate: 2019-12-13

Groothuis J, Pfeiffer K, El Jundi B, et al (2019)

The Jewel Wasp Standard Brain: Average shape atlas and morphology of the female Nasonia vitripennis brain.

Arthropod structure & development, 51:41-51.

Nasonia, a genus of parasitoid wasps, is a promising model system in the study of developmental and evolutionary genetics, as well as complex traits such as learning. Of these "jewel wasps", the species Nasonia vitripennis is widely spread and widely studied. To accelerate neuroscientific research in this model species, fundamental knowledge of its nervous system is needed. To this end, we present an average standard brain of recently eclosed naïve female N. vitripennis wasps obtained by the iterative shape averaging method. This "Jewel Wasp Standard Brain" includes the optic lobe (excluding the lamina), the anterior optic tubercle, the antennal lobe, the lateral horn, the mushroom body, the central complex, and the remaining unclassified neuropils in the central brain. Furthermore, we briefly describe these well-defined neuropils and their subregions in the N. vitripennis brain. A volumetric analysis of these neuropils is discussed in the context of brains of other insect species. The Jewel Wasp Standard Brain will provide a framework to integrate and consolidate the results of future neurobiological studies in N. vitripennis. In addition, the volumetric analysis provides a baseline for future work on age- and experience-dependent brain plasticity.

RevDate: 2019-09-08

Streinzer M, Roth N, Paulus HF, et al (2019)

Color preference and spatial distribution of glaphyrid beetles suggest a key role in the maintenance of the color polymorphism in the peacock anemone (Anemone pavonina, Ranunculaceae) in Northern Greece.

Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology, 205(5):735-743.

In the Mediterranean region, a group of unrelated plant species share an unusual deep-red flower color and are pollinated by glaphyrid beetles. Some of these species possess different color morphs, but the mechanisms maintaining this color polymorphism are unknown. The peacock anemone, Anemone pavonina, is a color polymorphic species with red or purple flowers. We investigated the spatial distribution of its color morphs and its potential glaphyrid pollinators, Pygopleurus spp., along an elevational gradient on the southern slopes of Mount Olympus, Greece. We found a correlation between relative proportions of the two color morphs with both elevation and beetle abundance. At low elevations (< 1000 m a.s.l.), beetles were abundant and anemone populations comprised only red flowers. Above a steep transition zone with mixed-colored populations (c. 1000-1300 m) most flowers were purple and beetles were rare. Color-trapping experiments revealed a strong preference for red over other colors in beetles and colorimetric modeling suggests that a simple chromatic mechanism is sufficient to explain their color choices. We thus hypothesize that beetles select for red flowers and that with increasing elevation and decreasing beetle density, other flower visitors (e.g., bees) gain importance as pollinators and select for a different color.

RevDate: 2019-10-10
CmpDate: 2019-10-09

Lyutova R, Selcho M, Pfeuffer M, et al (2019)

Reward signaling in a recurrent circuit of dopaminergic neurons and peptidergic Kenyon cells.

Nature communications, 10(1):3097 pii:10.1038/s41467-019-11092-1.

Dopaminergic neurons in the brain of the Drosophila larva play a key role in mediating reward information to the mushroom bodies during appetitive olfactory learning and memory. Using optogenetic activation of Kenyon cells we provide evidence that recurrent signaling exists between Kenyon cells and dopaminergic neurons of the primary protocerebral anterior (pPAM) cluster. Optogenetic activation of Kenyon cells paired with odor stimulation is sufficient to induce appetitive memory. Simultaneous impairment of the dopaminergic pPAM neurons abolishes appetitive memory expression. Thus, we argue that dopaminergic pPAM neurons mediate reward information to the Kenyon cells, and in turn receive feedback from Kenyon cells. We further show that this feedback signaling is dependent on short neuropeptide F, but not on acetylcholine known to be important for odor-shock memories in adult flies. Our data suggest that recurrent signaling routes within the larval mushroom body circuitry may represent a mechanism subserving memory stabilization.

RevDate: 2019-12-27

Princen SA, Oliveira RC, Ernst UR, et al (2019)

Honeybees possess a structurally diverse and functionally redundant set of queen pheromones.

Proceedings. Biological sciences, 286(1905):20190517.

Queen pheromones, which signal the presence of a fertile queen and induce workers to remain sterile, play a key role in regulating reproductive division of labour in insect societies. In the honeybee, volatiles produced by the queen's mandibular glands have been argued to act as the primary sterility-inducing pheromones. This contrasts with evidence from other groups of social insects, where specific queen-characteristic hydrocarbons present on the cuticle act as conserved queen signals. This led us to hypothesize that honeybee queens might also employ cuticular pheromones to stop workers from reproducing. Here, we support this hypothesis with the results of bioassays with synthetic blends of queen-characteristic alkenes, esters and carboxylic acids. We show that all these compound classes suppress worker ovary development, and that one of the blends of esters that we used was as effective as the queen mandibular pheromone (QMP) mix. Furthermore, we demonstrate that the two main QMP compounds 9-ODA and 9-HDA tested individually were as effective as the blend of all four major QMP compounds, suggesting considerable signal redundancy. Possible adaptive reasons for the observed complexity of the honeybee queen signal mix are discussed.

RevDate: 2019-06-19

Streinzer M, Chakravorty J, Neumayer J, et al (2019)

Species composition and elevational distribution of bumble bees (Hymenoptera, Apidae, Bombus Latreille) in the East Himalaya, Arunachal Pradesh, India.

ZooKeys, 851:71-89 pii:32956.

The East Himalaya is one of the world's most biodiverse ecosystems. However, very little is known about the abundance and distribution of many plant and animal taxa in this region. Bumble bees are a group of cold-adapted and high elevation insects that fulfil an important ecological and economical function as pollinators of wild and agricultural flowering plants and crops. The Himalayan mountain range provides ample suitable habitats for bumble bees. Systematic study of Himalayan bumble bees began a few decades ago and the main focus has centred on the western region, while the eastern part of the mountain range has received little attention and only a few species have been verified. During a three-year survey, more than 700 bumble bee specimens of 21 species were collected in Arunachal Pradesh, the largest of the north-eastern states of India. The material included a range of species that were previously known from a limited number of collected specimens, which highlights the unique character of the East Himalayan ecosystem. Our results are an important first step towards a future assessment of species distribution, threat, and conservation. Clear elevation patterns of species diversity were observed, which raise important questions about the functional adaptations that allow bumble bees to thrive in this particularly moist region in the East Himalaya.

RevDate: 2019-07-06

Stöckl A, Grittner R, K Pfeiffer (2019)

The role of lateral optic flow cues in hawkmoth flight control.

The Journal of experimental biology, 222(Pt 13): pii:jeb.199406.

Flying animals require sensory feedback on changes of their body position, as well as on their distance from nearby objects. The apparent image motion, or optic flow, which is generated as animals move through the air, can provide this information. Flight tunnel experiments have been crucial for our understanding of how insects use optic flow for flight control in confined spaces. However, previous work mainly focused on species from two insect orders: Hymenoptera and Diptera. We therefore set out to investigate whether the previously described control strategies to navigate enclosed environments are also used by insects with a different optical system, flight kinematics and phylogenetic background. We tested the role of lateral visual cues for forward flight control in the hummingbird hawkmoth Macroglossum stellatarum (Sphingidae, Lepidoptera), which possesses superposition compound eyes, and has the ability to hover in addition to its capacity for fast forward flight. Our results show that hawkmoths use a similar strategy for lateral position control to bees and flies in balancing the magnitude of translational optic flow perceived in both eyes. However, the influence of lateral optic flow on flight speed in hawkmoths differed from that in bees and flies. Moreover, hawkmoths showed individually attributable differences in position and speed control when the presented optic flow was unbalanced.

RevDate: 2020-01-16

George EA, Bröger AK, Thamm M, et al (2020)

Inter-individual variation in honey bee dance intensity correlates with expression of the foraging gene.

Genes, brain, and behavior, 19(1):e12592.

Individual behavioural differences in responding to the same stimuli is an integral part of division of labour in eusocial insect colonies. Amongst honey bee nectar foragers, individuals strongly differ in their sucrose responsiveness, which correlates with strong differences in behavioural decisions. In this study, we explored whether the mechanisms underlying the regulation of foraging are linked to inter-individual differences in the waggle dance activity of honey bee foragers. We first quantified the variation in dance activity amongst groups of foragers visiting an artificial feeder filled consecutively with different sucrose concentrations. We then determined, for these foragers, the sucrose responsiveness and the brain expression levels of three genes associated with food search and foraging; the foraging gene Amfor, octopamine receptor gene AmoctαR1 and insulin receptor AmInR-2. As expected, foragers showed large inter-individual differences in their dance activity, irrespective of the reward offered at the feeder. The sucrose responsiveness correlated positively with the intensity of the dance activity at the higher reward condition, with the more responsive foragers having a higher intensity of dancing. Out of the three genes tested, Amfor expression significantly correlated with dance activity, with more active dancers having lower expression levels. Our results show that dance and foraging behaviour in honey bees have similar mechanistic underpinnings and supports the hypothesis that the social communication behaviour of honey bees might have evolved by co-opting behavioural modules involved in food search and foraging in solitary insects.

RevDate: 2019-12-22

Smith CC, Weber JN, Mikheyev AS, et al (2019)

Landscape genomics of an obligate mutualism: Concordant and discordant population structures between the leafcutter ant Atta texana and its two main fungal symbiont types.

Molecular ecology, 28(11):2831-2845.

To explore landscape genomics at the range limit of an obligate mutualism, we use genotyping-by-sequencing (ddRADseq) to quantify population structure and the effect of host-symbiont interactions between the northernmost fungus-farming leafcutter ant Atta texana and its two main types of cultivated fungus. Genome-wide differentiation between ants associated with either of the two fungal types is of the same order of magnitude as differentiation associated with temperature and precipitation across the ant's entire range, suggesting that specific ant-fungus genome-genome combinations may have been favoured by selection. For the ant hosts, we found a broad cline of genetic structure across the range, and a reduction of genetic diversity along the axis of range expansion towards the range margin. This population-genetic structure was concordant between the ants and one cultivar type (M-fungi, concordant clines) but discordant for the other cultivar type (T-fungi). Discordance in population-genetic structures between ant hosts and a fungal symbiont is surprising because the ant farmers codisperse with their vertically transmitted fungal symbionts. Discordance implies that (a) the fungi disperse also through between-nest horizontal transfer or other unknown mechanisms, and (b) genetic drift and gene flow can differ in magnitude between each partner and between different ant-fungus combinations. Together, these findings imply that variation in the strength of drift and gene flow experienced by each mutualistic partner affects adaptation to environmental stress at the range margin, and genome-genome interactions between host and symbiont influence adaptive genetic differentiation of the host during range evolution in this obligate mutualism.

RevDate: 2019-12-02
CmpDate: 2019-12-02

Kappeler PM, Fichtel C, van Vugt M, et al (2019)

Female leadership: A transdisciplinary perspective.

Evolutionary anthropology, 28(4):160-163.

RevDate: 2019-11-20

Sanchez LM (2019)

Darwin's politics of selection.

Politics and the life sciences : the journal of the Association for Politics and the Life Sciences, 38(1):72-102.

The uses of natural selection argument in politics have been constant since Charles Darwin's times. They have also been varied. The readings of Darwin's theory range from the most radically individualist views, as in orthodox socio-Darwinism, to the most communitarian, as in Peter Kropotkin's and other socialist perspectives. This essay argues that such diverse, contradictory, and sometimes even outrageous political derivations from Darwin's theory may be partially explained by some incompleteness and ambivalences underlying Darwin's concepts. "Natural selection," "struggle for existence," and "survival of the fittest" are open concepts and may suggest some hierarchical and segregationist interpretations. Circumstantially, Darwin accepted social "checks," such as discouraging marriage of "lower" individuals to prevent them from reproducing, in a vein of Malthusian politics. This makes Darwin's theory of selection by struggle collide with his theory of social instincts, by which he explains the origins of morality. It also favors reading Darwin's On the Origin of Species or The Descent of Man from opposite, mostly ideological perspectives. Darwin's position is ambivalent, although hardly unreasonable. The recognition he makes of social instincts, as well as the use of the concept of artificial selection, entails accepting the role of human consciousness, by which social evolution cannot be reduced to natural evolution, as socio-Darwinians did next and as some neo-Darwinists seem to repeat. On these grounds, this essay argues the inadequacy of the conventional model of natural selection for understanding politics. If we want to describe politics in Darwin's language, artificial rather than natural selection would be the concept that performs better for explaining the courses of politics in real society.

RevDate: 2020-01-14
CmpDate: 2020-01-14

Hofman MPG, Hayward MW, Heim M, et al (2019)

Right on track? Performance of satellite telemetry in terrestrial wildlife research.

PloS one, 14(5):e0216223 pii:PONE-D-18-33139.

Satellite telemetry is an increasingly utilized technology in wildlife research, and current devices can track individual animal movements at unprecedented spatial and temporal resolutions. However, as we enter the golden age of satellite telemetry, we need an in-depth understanding of the main technological, species-specific and environmental factors that determine the success and failure of satellite tracking devices across species and habitats. Here, we assess the relative influence of such factors on the ability of satellite telemetry units to provide the expected amount and quality of data by analyzing data from over 3,000 devices deployed on 62 terrestrial species in 167 projects worldwide. We evaluate the success rate in obtaining GPS fixes as well as in transferring these fixes to the user and we evaluate failure rates. Average fix success and data transfer rates were high and were generally better predicted by species and unit characteristics, while environmental characteristics influenced the variability of performance. However, 48% of the unit deployments ended prematurely, half of them due to technical failure. Nonetheless, this study shows that the performance of satellite telemetry applications has shown improvements over time, and based on our findings, we provide further recommendations for both users and manufacturers.

RevDate: 2019-11-20

Becker MC, Rössler W, MF Strube-Bloss (2019)

UV light perception is modulated by the odour element of an olfactory-visual compound in restrained honeybees.

The Journal of experimental biology, 222(Pt 10): pii:jeb.201483.

Honeybees use visual and olfactory cues to detect flowers during foraging trips. Hence, the reward association of a nectar source is a multimodal construct which has at least two major components - olfactory and visual cues. How both sensory modalities are integrated to form a common reward association and whether and how they may interfere, is an open question. The present study used stimulation with UV, blue and green light to evoke distinct photoreceptor activities in the compound eye and two odour components (geraniol, citronellol). To test if a compound of both modalities is perceived as the sum of its elements (elemental processing) or as a unique cue (configural processing), we combined monochromatic light with single odour components in positive (PP) and negative patterning (NP) experiments. During PP, the compound of two modalities was rewarded, whereas the single elements were not. For NP, stimuli comprising a single modality were rewarded, whereas the olfactory-visual compound was not. Furthermore, we compared the differentiation abilities between two light stimuli that were or were not part of an olfactory-visual compound. Interestingly, the behavioural performances revealed a prominent case of configural processing, but only in those cases when UV light was an element of an olfactory-visual compound. Instead, learning with green- and blue-containing compounds rather supports elemental processing theory.

RevDate: 2019-11-20

Modlmeier AP, Colman E, Hanks EM, et al (2019)

Ant colonies maintain social homeostasis in the face of decreased density.

eLife, 8: pii:38473.

Interactions lie at the heart of social organization, particularly in ant societies. Interaction rates are presumed to increase with density, but there is little empirical evidence for this. We manipulated density within carpenter ant colonies of the species Camponotus pennsylvanicus by quadrupling nest space and by manually tracking 6.9 million ant locations and over 3200 interactions to study the relationship between density, spatial organization and interaction rates. Colonies divided into distinct spatial regions on the basis of their underlying spatial organization and changed their movement patterns accordingly. Despite a reduction in both overall and local density, we did not find the expected concomitant reduction in interaction rates across all colonies. Instead, we found divergent effects across colonies. Our results highlight the remarkable organizational resilience of ant colonies to changes in density, which allows them to sustain two key basic colony life functions, that is food and information exchange, during environmental change.

RevDate: 2019-11-20

Sperber AL, Kappeler PM, C Fichtel (2019)

Should I stay or should I go? Individual movement decisions during group departures in red-fronted lemurs.

Royal Society open science, 6(3):180991 pii:rsos180991.

Collective movements are essential for maintaining group cohesion. However, group members can have different optimal departure times, depending on individual, social and contextual factors whose relative importance remains poorly known. We, therefore, studied collective departures in four groups of red-fronted lemurs (Eulemur rufifrons) in Kirindy Forest, Madagascar, to investigate the influence of an individual's age, sex, their affiliative relationships and their proximity to other group members at the time of departure on their individual departure decision. We recorded behavioural and spatial data on individual departures during 167 group movements and conducted group scans (181-279 per group) to assess affiliative relationships. All factors influenced individual departures. Both affiliation and proximity determined a mimetic joining process in which dyads with stronger affiliative bonds departed in closer succession, and individuals followed the initiator and predecessors more quickly when they were in closer proximity at departure. While the influence of affiliation is common, the effect of inter-individual distance has rarely been considered in groups with heterogeneous social relationships. Although local rules influenced joining, the overall movement pattern was mainly determined by individual traits: juveniles took protected central positions, while females made up the van and males brought up the rear. Individual needs, expressed in the departure order, to an extent overruled the effect of affiliation. These results highlight the importance of considering individual, social and contextual factors collectively in the study of collective movements.

RevDate: 2019-11-20

McEniery DF (2019)

The 'Scientific' phrenologist - Bernard Hollander (1864-1934).

Journal of medical biography [Epub ahead of print].

Bernard Hollander (1864-1934), a Viennese-born British physician, scientist, and author, was best known for his late 19th century and early 20th century revival of a 'Scientific Phrenology'. Hollander, motivated by the advances in cerebral localisation and neuroscience that appeared to justify Franz Joseph Gall's (1758-1828) initial interests in craniology, hoped to use this new framework to substantively improve the lot of his patients and his community. Ridiculed and derided by his colleagues while maintaining a measure of public prominence, Hollander discussed contemporary issues including notions of human nature, mental illness, education, development, women's rights, and sociobiology. The current work focuses on Hollander, his writings, and his reception by the contemporary medical and lay community.

RevDate: 2019-11-20

Cox AR, R Montgomerie (2019)

The cases for and against double-blind reviews.

PeerJ, 7:e6702 pii:6702.

To date, the majority of authors on scientific publications have been men. While much of this gender bias can be explained by historic sexism and discrimination, there is concern that women may still be disadvantaged by the peer review process if reviewers' biases lead them to reject publications with female authors more often. One potential solution to this perceived gender bias in the reviewing process is for journals to adopt double-blind reviews whereby neither the authors nor the reviewers are aware of each other's identity and gender. To test the efficacy of double-blind reviews in one behavioral ecology journal (Behavioral Ecology, BE), we assigned gender to every authorship of every paper published for 2010-2018 in that journal compared to four other journals with single-blind reviews but similar subject matter and impact factors. While female authorships comprised only 35% of the total in all journals, the double-blind journal (BE) did not have more female authorships than its single-blind counterparts. Interestingly, the incidence of female authorship is higher at behavioral ecology journals (BE and Behavioral Ecology and Sociobiology) than in the ornithology journals (Auk, Condor, Ibis) for papers on all topics as well as those on birds. These analyses suggest that double-blind review does not currently increase the incidence of female authorship in the journals studied here. We conclude, at least for these journals, that double-blind review no longer benefits female authors and we discuss the pros and cons of the double-blind reviewing process based on our findings.

RevDate: 2019-10-28

Yilmaz A, Grübel K, Spaethe J, et al (2019)

Distributed plasticity in ant visual pathways following colour learning.

Proceedings. Biological sciences, 286(1896):20182813.

Colour processing at early stages of visual pathways is a topic of intensive study both in vertebrate and invertebrate species. However, it is still unclear how colour learning and memory formation affects an insect brain in the peripheral processing stages and high-order integration centres, and whether associative colour experiences are reflected in plasticity of underlying neuronal circuits. To address this issue, we used Camponotus blandus ants as their proven colour learning and memory capabilities, precisely controllable age and experience, and already known central visual pathways offer unique access to analyse plasticity in neuronal circuits for colour vision in a miniature brain. The potential involvement of distinct neuropils-optic lobes (OLs), mushroom body (MB) input (collar) and output (vertical lobe), anterior optic tubercle (AOTU) and central complex (CX)-in associative colour experiences was assessed by quantification of volumetric and synaptic changes (MB collar) directly after colour conditioning and, 3 days later, after the establishment of long-term memory (LTM). To account for potential effects of non-associative light exposure, we compared neuronal changes in the brain of colour-naive foragers with those of foragers that had been exposed to light in a non-associative way. The results clearly show that the OLs, AOTU, and CX respond with plastic changes after colour learning and LTM formation. This suggests a complex neuronal network for colour learning and memory formation involving multiple brain levels. Such a colour-processing network probably represents an efficient design promoting fast and accurate behavioural decisions during orientation and navigation.

RevDate: 2019-11-20

Kraft N, Spaethe J, Rössler W, et al (2019)

Neuronal Plasticity in the Mushroom-Body Calyx of Bumble Bee Workers During Early Adult Development.

Developmental neurobiology, 79(4):287-302.

Division of labor among workers is a key feature of social insects and frequently characterized by an age-related transition between tasks, which is accompanied by considerable structural changes in higher brain centers. Bumble bees (Bombus terrestris), in contrast, exhibit a size-related rather than an age-related task allocation, and thus workers may already start foraging at two days of age. We ask how this early behavioral maturation and distinct size variation are represented at the neuronal level and focused our analysis on the mushroom bodies (MBs), brain centers associated with sensory integration, learning and memory. To test for structural neuronal changes related to age, light exposure, and body size, whole-mount brains of age-marked workers were dissected for synapsin immunolabeling. MB calyx volumes, densities, and absolute numbers of olfactory and visual projection neuron (PN) boutons were determined by confocal laser scanning microscopy and three-dimensional image analyses. Dark-reared bumble bee workers showed an early age-related volume increase in olfactory and visual calyx subcompartments together with a decrease in PN-bouton density during the first three days of adult life. A 12:12 h light-dark cycle did not affect structural organization of the MB calyces compared to dark-reared individuals. MB calyx volumes and bouton numbers positively correlated with body size, whereas bouton density was lower in larger workers. We conclude that, in comparison to the closely related honey bees, neuronal maturation in bumble bees is completed at a much earlier stage, suggesting a strong correlation between neuronal maturation time and lifestyle in both species.

RevDate: 2019-06-24

Ruedenauer FA, Leonhardt SD, Lunau K, et al (2019)

Bumblebees are able to perceive amino acids via chemotactile antennal stimulation.

Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology, 205(3):321-331.

Like all animals, bees need to consume essential amino acids to maintain their body's protein synthesis. Perception and discrimination of amino acids are, however, still poorly understood in bees (and insects in general). We used chemotactile conditioning of the proboscis extension response (PER) to examine (1) whether Bombus terrestris workers are able to perceive amino acids by means of their antennae and (if so) which ones, (2) whether they are able to differentiate between different amino acids, and (3) whether they are able to differentiate between different concentrations of the same amino acid. We found that workers perceived asparagine, cysteine, hydroxyproline, glutamic acid, lysine, phenylalanine, and serine, but not alanine, leucine, proline, or valine by means of their antennae. Surprisingly, they were unable to differentiate between different (perceivable) amino acids, but they distinguished between different concentrations of lysine. Consequently, bumblebees seem to possess amino acid receptors at the tip of their antennae, which enable a general perception of those solute amino acids that have an additional functional group (besides the common amino and carboxylic groups). They may thus have the ability to assess the overall amino acid content of pollen and nectar prior to ingestion.

RevDate: 2019-07-01
CmpDate: 2019-07-01

Hesselbach H, R Scheiner (2019)

The novel pesticide flupyradifurone (Sivanto) affects honeybee motor abilities.

Ecotoxicology (London, England), 28(3):354-366.

Honeybees and other pollinators are threatened by changing landscapes and pesticides resulting from intensified agriculture. In 2018 the European Union prohibited the outdoor use of three neonicotinoid insecticides due to concerns about pollinators. A new pesticide by the name of "Sivanto" was recently released by Bayer AG. Its active ingredient flupyradifurone binds to the nicotinic acetylcholine receptor (AchR) in the honeybee brain, similar to neonicotinoids. Nevertheless, flupyradifurone is assumed to be harmless for honeybees and can even be applied on flowering crops. So far, only little has been known about sublethal effects of flupyradifurone on honeybees. Intact motor functions are decisive for numerous behaviors including foraging and dancing. We therefore selected a motor assay to investigate in how far sublethal doses of this pesticide affect behavior in young summer and long-lived winter honeybees. Our results demonstrate that flupyradifurone (830 µmol/l) can evoke motor disabilities and disturb normal motor behavior after a single oral administration (1.2 µg/bee). These effects are stronger in long-lived winter bees than in young summer bees. After offering an equal amount of pesticide (1.0-1.75 µg) continuously over 24 h with food the observed effects are slighter. For comparisons we repeated our experiments with the neonicotinoid imidacloprid. Intriguingly, the alterations in behavior induced by this pesticide (4 ng/bee) were different and longer-lasting compared to flupyradifurone, even though both substances bind to nicotinic acetylcholine receptors.

RevDate: 2019-10-31

Lichtenstein L, Brockmann A, J Spaethe (2019)

Learning of monochromatic stimuli in Apis cerana and Apis mellifera by means of PER conditioning.

Journal of insect physiology, 114:30-34.

Honey bees are globally distributed and have received increased attention due to their high economic and ecological value for pollination, their exceptional eusocial lifestyle and complex behavioral repertoire. Interestingly, most research on learning and memory in honey bees has been performed in the Western honey bee, Apis mellifera L., and other honey bee species were largely neglected. In the current study, we thus compared visual learning performance of A. mellifera and the Eastern honey bee, A. cerana Fabr., using the proboscis extension response (PER) paradigm. Workers of A. mellifera and A. cerana were differentially conditioned to two monochromatic light stimuli, with peak maxima at 435 and 528 nm. Both honey bee species were able to form an association between the color stimulus and a sugar reward and significantly distinguished between the two color stimuli in a differential discrimination test. However, besides similar performance levels during visual learning, A. cerana showed a reduced mid-term memory (tested after 2 h) compared to A. mellifera. Finally, performance of the visual PER conditioning in our study reached similar levels as found in olfactory PER conditioning, and we thus recommend the visual PER conditioning approach in addition to olfactory conditioning as a useful tool for studying species-specific learning and memory capabilities in honey bees under controlled laboratory conditions.

RevDate: 2019-11-20

Pegel U, Pfeiffer K, Zittrell F, et al (2019)

Two Compasses in the Central Complex of the Locust Brain.

The Journal of neuroscience : the official journal of the Society for Neuroscience, 39(16):3070-3080.

Many migratory insects rely on a celestial compass for spatial orientation. Several features of the daytime sky, all generated by the sun, can be exploited for navigation. Two of these are the position of the sun and the pattern of polarized skylight. Neurons of the central complex (CX), a group of neuropils in the central brain of insects, have been shown to encode sky compass cues. In desert locusts, the CX holds a topographic, compass-like representation of the plane of polarized light (E-vector) presented from dorsal direction. In addition, these neurons also encode the azimuth of an unpolarized light spot, likely representing the sun. Here, we investigate whether, in addition to E-vector orientation, the solar azimuth is represented topographically in the CX. We recorded intracellularly from eight types of CX neuron while stimulating animals of either sex with polarized blue light from zenithal direction and an unpolarized green light spot rotating around the animal's head at different elevations. CX neurons did not code for elevation of the unpolarized light spot. However, two types of columnar neuron showed a linear correlation between innervated slice in the CX and azimuth tuning to the unpolarized green light spot, consistent with an internal compass representation of solar azimuth. Columnar outputs of the CX also showed a topographic representation of zenithal E-vector orientation, but the two compasses were not linked to each other. Combined stimulation with unpolarized green and polarized blue light suggested that the two compasses interact in a nonlinear way.SIGNIFICANCE STATEMENT In the brain of the desert locust, neurons sensitive to the plane of celestial polarization are arranged like a compass in the slices of the central complex (CX). These neurons, in addition, code for the horizontal direction of an unpolarized light cue possibly representing the sun. We show here that horizontal directions are, in addition to E-vector orientations from the dorsal direction, represented in a compass-like manner across the slices of the CX. However, the two compasses are not linked to each other, but rather seem to interact in a cell-specific, nonlinear way. Our study confirms the role of the CX in signaling heading directions and shows that different cues are used for this task.

RevDate: 2019-09-06
CmpDate: 2019-09-05

Contreras-Pulache H, Espinoza-Lecca E, J Sevillano-Jimenez (2018)

[Notes on the historical evolution of the work of Pedro Ortiz Cabanillas and his sociobiological informational theory].

Revista peruana de medicina experimental y salud publica, 35(4):699-706.

The Informational Sociobiological Theory proposes a radically-different definition of living systems and, therefore, is the only existing neurological theory that evades the mind-brain problem and explains the nature of human consciousness. It was developed by Pedro Ortiz Cabanillas between 1984 and 2011. In this document we are presenting a listing of his main works. We include, additionally, unpublished material of the years 1998, 1999, 2006, and 2009.

RevDate: 2019-11-20

Kappeler PM, Nunn CL, Vining AQ, et al (2019)

Evolutionary dynamics of sexual size dimorphism in non-volant mammals following their independent colonization of Madagascar.

Scientific reports, 9(1):1454 pii:10.1038/s41598-018-36246-x.

As predicted by sexual selection theory, males are larger than females in most polygynous mammals, but recent studies found that ecology and life history traits also affect sexual size dimorphism (SSD) through evolutionary changes in either male size, female size, or both. The primates of Madagascar (Lemuriformes) represent the largest group of mammals without male-biased SSD. The eco-evo-devo hypothesis posited that adaptations to unusual climatic unpredictability on Madagascar have ultimately reduced SSD in lemurs after dispersing to Madagascar, but data have not been available for comparative tests of the corresponding predictions that SSD is also absent in other terrestrial Malagasy mammals and that patterns of SSD changed following the colonization of Madagascar. We used phylogenetic methods and new body mass data to test these predictions among the four endemic radiations of Malagasy primates, carnivorans, tenrecs, and rodents. In support of our prediction, we found that male-biased SSD is generally absent among all Malagasy mammals. Phylogenetic comparative analyses further indicated that after their independent colonization of Madagascar, SSD decreased in primates and tenrecs, but not in the other lineages or when analyzed across all species. We discuss several mechanisms that may have generated these patterns and conclude that neither the eco-evo-devo hypothesis, founder effects, the island rule nor sexual selection theory alone can provide a compelling explanation for the observed patterns of SSD in Malagasy mammals.

RevDate: 2020-01-13

Grodwohl JB (2019)

Animal Behavior, Population Biology and the Modern Synthesis (1955-1985).

Journal of the history of biology, 52(4):597-633.

This paper examines the history of animal behavior studies after the synthesis period. Three episodes are considered: the adoption of the theory of natural selection, the mathematization of ideas, and the spread of molecular methods in behavior studies. In these three episodes, students of behavior adopted practices and standards developed in population ecology and population genetics. While they borrowed tools and methods from these fields, they made distinct uses (inclusive fitness method, evolutionary theory of games, emphasis on individual selection) that set them relatively apart and led them to contribute, in their own way, to evolutionary theory. These episodes also highlight some limitations of "conjunction narratives" centered on the relation between a discipline and the modern synthesis. A trend in conjunction narratives is to interpret any development related to evolution in a discipline as an "extension," an "integration," or as a "delayed" synthesis. I here suggest that this can lead to underestimate discontinuities in the history of evolutionary biology.

RevDate: 2019-01-30
CmpDate: 2019-01-30

Römer D, F Roces (2019)

Waste deposition in leaf-cutting ants is guided by olfactory cues from waste.

Die Naturwissenschaften, 106(1-2):3 pii:10.1007/s00114-018-1599-0.

Social insects often use olfactory cues from their environment to coordinate colony tasks. We investigated whether leaf-cutting ants use volatiles as cues to guide the deposition of their copious amounts of colony refuse. In the laboratory, we quantified the relocation of a small pile of colony waste by workers of Atta laevigata towards volatiles offered at each side of the pile as a binary choice, consisting of either waste volatiles, fungus volatiles, or no volatiles. Fungus volatiles alone did not evoke relocation of waste. Waste volatiles alone, by contrast, led to a strong relocation of waste particles towards them. When fungus and waste volatiles were tested against each other, waste particles were also relocated towards waste volatiles, and in a high percentage of assays completely moved away from the source of fungus volatiles as compared to the previous series. We suggest that deposition and accumulation of large amounts of refuse in single external heaps or a few huge underground waste chambers of Atta nests is due to both olfactory preferences and stigmergic responses towards waste volatiles by waste-carrying workers.

RevDate: 2019-04-03
CmpDate: 2019-04-03

Keller A, Brandel A, Becker MC, et al (2018)

Wild bees and their nests host Paenibacillus bacteria with functional potential of avail.

Microbiome, 6(1):229 pii:10.1186/s40168-018-0614-1.

BACKGROUND: In previous studies, the gram-positive firmicute genus Paenibacillus was found with significant abundances in nests of wild solitary bees. Paenibacillus larvae is well-known for beekeepers as a severe pathogen causing the fatal honey bee disease American foulbrood, and other members of the genus are either secondary invaders of European foulbrood or considered a threat to honey bees. We thus investigated whether Paenibacillus is a common bacterium associated with various wild bees and hence poses a latent threat to honey bees visiting the same flowers.

RESULTS: We collected 202 samples from 82 individuals or nests of 13 bee species at the same location and screened each for Paenibacillus using high-throughput sequencing-based 16S metabarcoding. We then isolated the identified strain Paenibacillus MBD-MB06 from a solitary bee nest and sequenced its genome. We did find conserved toxin genes and such encoding for chitin-binding proteins, yet none specifically related to foulbrood virulence or chitinases. Phylogenomic analysis revealed a closer relationship to strains of root-associated Paenibacillus rather than strains causing foulbrood or other accompanying diseases. We found anti-microbial evidence within the genome, confirmed by experimental bioassays with strong growth inhibition of selected fungi as well as gram-positive and gram-negative bacteria.

CONCLUSIONS: The isolated wild bee associate Paenibacillus MBD-MB06 is a common, but irregularly occurring part of wild bee microbiomes, present on adult body surfaces and guts and within nests especially in megachilids. It was phylogenetically and functionally distinct from harmful members causing honey bee colony diseases, although it shared few conserved proteins putatively toxic to insects that might indicate ancestral predisposition for the evolution of insect pathogens within the group. By contrast, our strain showed anti-microbial capabilities and the genome further indicates abilities for chitin-binding and biofilm-forming, suggesting it is likely a useful associate to avoid fungal penetration of the bee cuticula and a beneficial inhabitant of nests to repress fungal threats in humid and nutrient-rich environments of wild bee nests.

RevDate: 2019-03-21
CmpDate: 2019-03-21

Ferretti V, F Papaleo (2019)

Understanding others: Emotion recognition in humans and other animals.

Genes, brain, and behavior, 18(1):e12544.

Emotion recognition represents the ability to encode an ensemble of sensory stimuli providing information about the emotional state of another individual. This ability is not unique to humans. An increasing number of studies suggest that many aspects of higher order social functions, including emotion recognition, might be present in species ranging from primates to rodents, indicating a conserved role in social animals. The aim of this review is to examine and compare how emotions are communicated and perceived in humans and other animals, with the intent to highlight possible new behavioral approaches and research perspectives. We summarize the evidence from human emotion recognition, and latest advances in the development of nonhuman animal behavioral tests, using or implying the use of this cognitive function. The differential implication of sensory modalities used by animals to communicate and decipher emotional states is also discussed. The opportunity to measure emotion recognition abilities in rodents may allow us to better identify the neural mechanisms mediating this complex function, thus promoting the development of new intervention strategies for several neuropsychiatric disorders characterized by social cognitive dysfunctions.

RevDate: 2019-02-21
CmpDate: 2019-02-21

Freas CA, Fleischmann PN, K Cheng (2019)

Experimental ethology of learning in desert ants: Becoming expert navigators.

Behavioural processes, 158:181-191.

Foraging desert ants are repeatedly presented with the challenge of leaving the nest, searching the scorching desert landscape to find food, and then transporting it back home. To accomplish this task, foragers have a navigational toolbox, which relies on olfactory, idiothetic, visual and magnetic cues. Desert ants have been widely studied with regards to these abilities, including a heavy focus on learned visual cues, the most prominent being the terrestrial panorama. Nest cues are first acquired during pre-foraging learning walks. Once foragers leave the nest area, they also learn a number of cues to aid them when returning both back to the nest and to known food sites, using experience of previous trips to navigate on future trips. In this review, we describe the learning processes involved in accurate navigation in desert ants. We first focus on recent research on nest-site panorama learning during pre-foraging learning walks as well as panorama learning away from the nest during foraging. We also review learning cues beyond the terrestrial panorama, including tactile, magnetic, olfactory and vibrational cues. These studies provide a basis for future work to further explore how these navigators, despite their small brains, acquire, retain and use many cue sets present in their environments. We call for more experimental ethology focussed on learning processes, both by exploring run-by-run and step-by-step acquisition of information for navigation, as well as for other natural tasks in an animal's life.

RevDate: 2019-10-28
CmpDate: 2019-10-28

Bastin F, Couto A, Larcher V, et al (2018)

Marked interspecific differences in the neuroanatomy of the male olfactory system of honey bees (genus Apis).

The Journal of comparative neurology, 526(18):3020-3034.

All honey bee species (genus Apis) display a striking mating behavior with the formation of male (drone) congregations, in which virgin queens mate with many drones. Bees' mating behavior relies on olfactory communication involving queen-but also drone pheromones. To explore the evolution of olfactory communication in Apis, we analyzed the neuroanatomical organization of the antennal lobe (primary olfactory center) in the drones of five species from the three main lineages (open-air nesting species: dwarf honey bees Apis florea and giant honey bees Apis dorsata; cavity-nesting species: Apis mellifera, Apis kochevnikovi, and Apis cerana) and from three populations of A. cerana (Borneo, Thailand, and Japan). In addition to differences in the overall number of morphological units, the glomeruli, our data reveal marked differences in the number and position of macroglomeruli, enlarged units putatively dedicated to sex pheromone processing. Dwarf and giant honey bee species possess two macroglomeruli while cavity-nesting bees present three or four macroglomeruli, suggesting an increase in the complexity of sex communication during evolution in the genus Apis. The three A. cerana populations showed differing absolute numbers of glomeruli but the same three macroglomeruli. Overall, we identified six different macroglomeruli in the genus Apis. One of these (called MGb), which is dedicated to the detection of the major queen compound 9-ODA in A. mellifera, was conserved in all species. We discuss the implications of these results for our understanding of sex communication in honey bees and propose a putative scenario of antennal lobe evolution in the Apis genus.

RevDate: 2019-04-10
CmpDate: 2019-04-10

Ruedenauer FA, Wöhrle C, Spaethe J, et al (2018)

Do honeybees (Apis mellifera) differentiate between different pollen types?.

PloS one, 13(11):e0205821.

Bees receive nectar and pollen as reward for pollinating plants. Pollen of different plant species varies widely in nutritional composition. In order to select pollen of appropriate nutritional quality, bees would benefit if they could distinguish different pollen types. Whether they rely on visual, olfactory and/or chemotactile cues to distinguish between different pollen types, has however been little studied. In this study, we examined whether and how Apis mellifera workers differentiate between almond and apple pollen. We used differential proboscis extension response conditioning with olfactory and chemotactile stimulation, in light and darkness, and in summer and winter bees. We found that honeybees were only able to differentiate between different pollen types, when they could use both chemotactile and olfactory cues. Visual cues further improved learning performance. Summer bees learned faster than winter bees. Our results thus highlight the importance of multisensory information for pollen discrimination.

RevDate: 2019-10-07
CmpDate: 2019-10-07

Egert-Berg K, Hurme ER, Greif S, et al (2018)

Resource Ephemerality Drives Social Foraging in Bats.

Current biology : CB, 28(22):3667-3673.e5.

Observations of animals feeding in aggregations are often interpreted as events of social foraging, but it can be difficult to determine whether the animals arrived at the foraging sites after collective search [1-4] or whether they found the sites by following a leader [5, 6] or even independently, aggregating as an artifact of food availability [7, 8]. Distinguishing between these explanations is important, because functionally, they might have very different consequences. In the first case, the animals could benefit from the presence of conspecifics, whereas in the second and third, they often suffer from increased competition [3, 9-13]. Using novel miniature sensors, we recorded GPS tracks and audio of five species of bats, monitoring their movement and interactions with conspecifics, which could be inferred from the audio recordings. We examined the hypothesis that food distribution plays a key role in determining social foraging patterns [14-16]. Specifically, this hypothesis predicts that searching for an ephemeral resource (whose distribution in time or space is hard to predict) is more likely to favor social foraging [10, 13-15] than searching for a predictable resource. The movement and social interactions differed between bats foraging on ephemeral versus predictable resources. Ephemeral species changed foraging sites and showed large temporal variation nightly. They aggregated with conspecifics as was supported by playback experiments and computer simulations. In contrast, predictable species were never observed near conspecifics and showed high spatial fidelity to the same foraging sites over multiple nights. Our results suggest that resource (un)predictability influences the costs and benefits of social foraging.

RevDate: 2019-02-19
CmpDate: 2019-02-18

Bang A (2019)

Antecedents of behavioural and reproductive dominance in pairs of the primitively eusocial wasp Ropalidia marginata.

Behavioural processes, 158:1-3.

What factors predispose some individuals to become reproductively dominant in a group where every member can reproduce? Antecedents of reproductive dominance have often been investigated in primitively eusocial species where reproductive skew exists despite adult reproductive potential displayed by every group-member, but such studies have rarely focused on small, incipient colonies. Here, I investigated antecedents of behavioural and reproductive dominance in pairs of the Indian paper wasp Ropalidia marginata. Common antecedents of behavioural dominance such as body size and age were inoperative in pairs of R. marginata. Moreover, age and behavioural dominance, but not body size, influenced reproductive dominance in pairs. These findings are not only different from other primitively eusocial insects, but also different from the colonies of R. marginata. It is likely that antecedents of reproductive dominance are different not only in different species, but also change with group size within a species, such that the role of behavioural dominance to achieve reproductive monopoly remains more effective in small groups such as pairs, and becomes less effective as the group size increases. These results require further investigations into the effect of group size on individual behaviour in group-living animals.

RevDate: 2019-04-04
CmpDate: 2019-04-04

Faragalla KM, Chernyshova AM, Gallo AJ, et al (2018)

From gene list to gene network: Recognizing functional connections that regulate behavioral traits.

Journal of experimental zoology. Part B, Molecular and developmental evolution, 330(6-7):317-329.

The study of social breeding systems is often gene focused, and the field of insect sociobiology has been successful at assimilating tools and techniques from molecular biology. One common output from sociogenomic studies is a gene list. Gene lists are readily generated from microarray, RNA sequencing, or other molecular screens that typically aim to prioritize genes based on the differences in their expression. Gene lists, however, are often unsatisfying because the information they provide is simply tabular and does not explain how genes interact with each other, or how genetic interactions change in real time under social or environmental circumstances. Here, we promote a view that is relatively common to molecular systems biology, where gene lists are converted into gene networks that better describe the functional connections that regulate behavioral traits. We present a narrative related to honeybee worker sterility to show how network analysis can be used to reprioritize candidate genes based on connectivity rather than their freestanding expression values. Networks can also reveal multigene modules, motifs, clusters or other system-wide properties that might not be apparent from an ab initio list. We argue that because network analyses are not restricted to "genes" as nodes, their implementation can potentially connect multiple levels of biological organization into a single, progressively complex study system.

RevDate: 2019-06-10
CmpDate: 2019-02-25

Sommerlandt FMJ, Brockmann A, Rössler W, et al (2019)

Immediate early genes in social insects: a tool to identify brain regions involved in complex behaviors and molecular processes underlying neuroplasticity.

Cellular and molecular life sciences : CMLS, 76(4):637-651.

Social insects show complex behaviors and master cognitive tasks. The underlying neuronal mechanisms, however, are in most cases only poorly understood due to challenges in monitoring brain activity in freely moving animals. Immediate early genes (IEGs) that get rapidly and transiently expressed following neuronal stimulation provide a powerful tool for detecting behavior-related neuronal activity in vertebrates. In social insects, like honey bees, and in insects in general, this approach is not yet routinely established, even though these genes are highly conserved. First studies revealed a vast potential of using IEGs as neuronal activity markers to analyze the localization, function, and plasticity of neuronal circuits underlying complex social behaviors. We summarize the current knowledge on IEGs in social insects and provide ideas for future research directions.

RevDate: 2019-10-07
CmpDate: 2019-10-03

Sehner S, Fichtel C, PM Kappeler (2018)

Primate tails: Ancestral state reconstruction and determinants of interspecific variation in primate tail length.

American journal of physical anthropology, 167(4):750-759.

OBJECTIVE: Living primates vary considerably in tail length-body size relation, ranging from tailless species to those where the tail is more than twice as long as the body. Because the general pattern and determinants of tail evolution remain incompletely known, we reconstructed evolutionary changes in relative tail length across all primates and sought to explain interspecific variation in this trait.

METHODS: We combined data on tail length, head-body length, intermembral index (IMI), habitat use, locomotion type, and range latitude for 340 species from published sources. We reconstructed the evolution of relative tail length to identify all independent cases of regime shifts on a primate phylogeny, using several methods based on Ornstein-Uhlenbeck (OU) models. Accounting for phylogeny, we also examined the effects of habitat, locomotion type, distance from the equator and IMI on interspecific variation in tail length-body size relation.

RESULTS: Primate tail length is not sexually dimorphic. A phylogenetic reconstruction allowing multiple optima explains the observed regime shifts best. During the evolutionary history of primates, relative tail length changed 50 times under an OU model. Specifically, relative tail length increased 26 and decreased 24 times. Most of these changes occurred among Old World primates. Among the variables tested here, interspecific variation in IMI and the difference between leaping and non-leaping locomotion explained interspecific variation in relative tail length: Evolutionary decreases in relative tail length are generally associated with an increase in IMI and an absence of leaping behavior.

CONCLUSIONS: Regime shifts for relative tail length in living primates occurred in concert with fundamental changes in IMI and a change from leaping to non-leaping locomotion, or vice versa. Exceptions from this general pattern are linked to the presence of a prehensile tail or specialized foraging strategies. Thus, the primate tail appears to have evolved in functional coordination with limb proportions, presumably to assist body balance.

RevDate: 2019-10-07
CmpDate: 2019-10-04

Bernaldo de Quirós E, Wheeler BC, Hammerschmidt K, et al (2018)

Do sexual calls in female black capuchin monkeys (Sapajus nigritus) vary with fertility? An acoustic analysis.

American journal of primatology, 80(9):e22920.

Females across a range of animal taxa produce vocalizations and signals uniquely associated with periods of mating. While such signals may ultimately function to increase female attractivity to males, conflicting findings challenge the extent to which these signals co-vary in accordance with the probability of conception. Female black capuchin monkeys (Sapajus nigritus) display an elaborate repertoire of both vocal and visual components as part of their socio-sexual behavior, and previous analyses have shown that the rates of production of visual, but not vocal, components provide graded information on female ovulation. It remains possible, however, that the acoustic parameters of these sexual calls, rather than their rate of productions, co-vary with female fertility. To test this, we analyzed structural and temporal call parameters from estrous calls and post-copulatory calls recorded over five consecutive mating seasons in 12 sexually mature females at Iguazú National Park, Argentina. Calls given during the fertile phase of the female ovarian cycle were compared with those given during the non-fertile phase, as determined by profiles of female reproductive hormones. Similarly, within the fertile phase, we tested whether temporal or spectral acoustic parameters of calls gradually change with the approach of ovulation. We did not find any significant relationship between call parameters and the two measures of female fertility in either female estrous calls or post-copulatory calls. However, some differences between pre- and post-copulatory calls were apparent. Overall, our results indicate that sexual calls in black capuchin females do not provide precise information about the timing of ovulation, but may allow listeners to make probabilistic inferences about whether copulations have taken place. This, combined with previous findings, suggests that females in our study may use signals in different modalities to convey information about their fertility and sexual behavior with varying degrees of precision.

RevDate: 2019-11-20

Henke-von der Malsburg J, C Fichtel (2018)

Are generalists more innovative than specialists? A comparison of innovative abilities in two wild sympatric mouse lemur species.

Royal Society open science, 5(8):180480.

The propensity to flexibly innovate behavioural variants might advantage animals when dealing with novel or modified ecological or social challenges. Interspecific innovative abilities can be predicted by the degree of ecological generalism and intraspecific variation is predicted by personality traits. To examine the effects of these factors on innovation, we compared problem-solving abilities in the generalist grey mouse lemurs (Microcebus murinus) and the more specialized Madame Berthe's mouse lemurs (Microcebus berthae) in western Madagascar. We examined personality traits by testing 54 individuals in open field and novel object tests, and we assessed problem-solving abilities by presenting an artificial feeding-box that could be opened by three different techniques. The first two techniques presented novel problems and the third technique a modified problem to the more complex second novel problem. In both species, motivation, early success and better inhibitory control characterized innovators and predicted superior problem-solving performance. Although both species performed equally well in finding a solution to the novel problems, the specialist species was more efficient in finding a novel solution to a familiar problem. Since the ecological specialist also exhibited more inhibitory control in this task than the generalist, we propose that specialists may dispose of more efficient problem-solving behaviour.

RevDate: 2019-08-29
CmpDate: 2019-07-08

Bernadou A, Schrader L, Pable J, et al (2018)

Stress and early experience underlie dominance status and division of labour in a clonal insect.

Proceedings. Biological sciences, 285(1885):.

Cooperation and division of labour are fundamental in the 'major transitions' in evolution. While the factors regulating cell differentiation in multi-cellular organisms are quite well understood, we are just beginning to unveil the mechanisms underlying individual specialization in cooperative groups of animals. Clonal ants allow the study of which factors influence task allocation without confounding variation in genotype and morphology. Here, we subjected larvae and freshly hatched workers of the clonal ant Platythyrea punctata to different rearing conditions and investigated how these manipulations affected division of labour among pairs of oppositely treated, same-aged clonemates. High rearing temperature, physical stress, injury and malnutrition increased the propensity of individuals to become subordinate foragers rather than dominant reproductives. This is reflected in changed gene regulation: early stages of division of labour were associated with different expression of genes involved in nutrient signalling pathways, metabolism and the phenotypic response to environmental stimuli. Many of these genes appear to be capable of responding to a broad range of stressors. They might link environmental stimuli to behavioural and phenotypic changes and could therefore be more broadly involved in caste differentiation in social insects. Our experiments also shed light on the causes of behavioural variation among genetically identical individuals.

RevDate: 2019-11-20

Heinze S, K Pfeiffer (2018)

Editorial: The Insect Central Complex-From Sensory Coding to Directing Movement.

Frontiers in behavioral neuroscience, 12:156.

RevDate: 2019-09-26
CmpDate: 2019-07-05

Huebner F, Fichtel C, PM Kappeler (2018)

Linking cognition with fitness in a wild primate: fitness correlates of problem-solving performance and spatial learning ability.

Philosophical transactions of the Royal Society of London. Series B, Biological sciences, 373(1756):.

Linking the cognitive performance of wild animals with fitness consequences is crucial for understanding evolutionary processes that shape individual variation in cognition. However, the few studies that have examined these links revealed differing relationships between various cognitive performance measures and fitness proxies. To contribute additional comparative data to this body of research, we linked individual performance during repeated problem-solving and spatial learning ability in a maze with body condition and survival in wild grey mouse lemurs (Microcebus murinus). All four variables exhibited substantial inter-individual variation. Solving efficiency in the problem-solving task, but not spatial learning performance, predicted the magnitude of change in body condition after the harsh dry season, indicating that the ability to quickly apply a newly discovered motor technique might also facilitate exploitation of new, natural food resources. Survival was not linked with performance in both tasks, however, suggesting that mouse lemurs' survival might not depend on the cognitive performances addressed here. Our study is the first linking cognition with fitness proxies in a wild primate species, and our discussion highlights the importance and challenges of accounting for a species' life history and ecology in choosing meaningful cognitive and fitness variables for a study in the wild.This article is part of the theme issue 'Causes and consequences of individual differences in cognitive abilities'.

RevDate: 2019-09-26
CmpDate: 2019-07-05

Cauchoix M, Chow PKY, van Horik JO, et al (2018)

The repeatability of cognitive performance: a meta-analysis.

Philosophical transactions of the Royal Society of London. Series B, Biological sciences, 373(1756):.

Behavioural and cognitive processes play important roles in mediating an individual's interactions with its environment. Yet, while there is a vast literature on repeatable individual differences in behaviour, relatively little is known about the repeatability of cognitive performance. To further our understanding of the evolution of cognition, we gathered 44 studies on individual performance of 25 species across six animal classes and used meta-analysis to assess whether cognitive performance is repeatable. We compared repeatability (R) in performance (1) on the same task presented at different times (temporal repeatability), and (2) on different tasks that measured the same putative cognitive ability (contextual repeatability). We also addressed whether R estimates were influenced by seven extrinsic factors (moderators): type of cognitive performance measurement, type of cognitive task, delay between tests, origin of the subjects, experimental context, taxonomic class and publication status. We found support for both temporal and contextual repeatability of cognitive performance, with mean R estimates ranging between 0.15 and 0.28. Repeatability estimates were mostly influenced by the type of cognitive performance measures and publication status. Our findings highlight the widespread occurrence of consistent inter-individual variation in cognition across a range of taxa which, like behaviour, may be associated with fitness outcomes.This article is part of the theme issue 'Causes and consequences of individual differences in cognitive abilities'.

RevDate: 2019-07-11
CmpDate: 2019-07-11

Kittler K, Kappeler PM, C Fichtel (2018)

Instrumental problem-solving abilities in three lemur species (Microcebus murinus, Varecia variegata, and Lemur catta).

Journal of comparative psychology (Washington, D.C. : 1983), 132(3):306-314.

Apes and some New and Old World monkeys (i.e., haplorhine primates) are known to routinely use tools. In strepsirrhine primates (i.e., lemurs and lorises), no tool use has been reported, even though they appear to have some basic understanding of the spatial relations required for using a pulling tool. To facilitate direct comparisons of the underlying abilities between haplorhine and strepsirrhine primate species, we experimentally examined instrumental problem-solving abilities in three captive lemur species (Microcebus murinus, Varecia variegata, and Lemur catta), using methods from previous experiments with haplorhine primates. First, lemurs were supposed to use a stick to gain access to an inaccessible food reward. Only one ring-tailed lemur solved this task spontaneously on the first attempt. After offering the stick repeatedly, 13 individuals of all three species solved it successfully. Second, lemurs had to choose between pairs of reachable objects with a food reward on or near them, where one object did not afford pulling in the food. Ring-tailed and gray mouse lemurs generally selected the correct (connected) object, thus performing comparably with haplorhine primates, and ruffed lemurs even matched chimpanzees in their performance. Thus, although strepsirrhine primates may lack the fine motor skills to use a stick as a reaching tool, they performed comparable with naturally tool-using haplorhine primates on means-end problems. Our findings suggest a dissociation in primates between the judgment of spatial relations between two objects, which appears to be roughly equivalent across species, and facility at handling sticks for instrumental purposes, which favors species with enhanced manual dexterity. (PsycINFO Database Record

RevDate: 2018-11-14
CmpDate: 2018-11-08

Peckre LR, Defolie C, Kappeler PM, et al (2018)

Potential self-medication using millipede secretions in red-fronted lemurs: combining anointment and ingestion for a joint action against gastrointestinal parasites?.

Primates; journal of primatology, 59(5):483-494.

Self-anointing, referring to the behaviour of rubbing a material object or foreign substance over different parts of the body, has been observed in several vertebrate species, including primates. Several functions, such as detoxifying a rich food source, social communication and protection against ectoparasites, have been proposed to explain this behaviour. Here, we report observations of six wild red-fronted lemurs (Eulemur rufifrons) of both sexes and different age classes anointing their perianal-genital areas and tails with chewed millipedes. Several individuals also ingested millipedes after prolonged chewing. In light of the features of the observed interactions with millipedes, and the nature and potential metabolic pathways of the released chemicals, we suggest a potential self-medicative function. Specifically, we propose that anointing combined with the ingestion of millipedes' benzoquinone secretions by red-fronted lemurs may act in a complementary fashion against gastrointestinal parasite infections, and more specifically Oxyuridae nematodes, providing both prophylactic and therapeutic effects.

RevDate: 2019-03-20
CmpDate: 2019-02-19

Thamm M, Sturm K, Schlossmann J, et al (2018)

Levels and activity of cyclic guanosine monophosphate-dependent protein kinase in nurse and forager honeybees.

Insect molecular biology, 27(6):815-823.

Age-dependent division of labour in honeybees was shown to be connected to sensory response thresholds. Foragers show a higher gustatory responsiveness than nurse bees. It is generally assumed that nutrition-related signalling pathways underlie this behavioural plasticity. Here, one important candidate gene is the foraging gene, which encodes a cyclic guanosine monophosphate-dependent protein kinase (PKG). Several roles of members of this enzyme family were analysed in vertebrates. They own functions in important processes such as growth, secretion and neuronal adaptation. Honeybee foraging messenger RNA expression is upregulated in the brain of foragers. In vivo activation of PKG can modulate gustatory responsiveness. We present for the first time PKG protein level and activity data in the context of social behaviour and feeding. Protein level was significantly higher in brains of foragers than in those of nurse bees, substantiating the role of PKG in behavioural plasticity. However, enzyme activity did not differ between behavioural roles. The mediation of feeding status appears independent of PKG signalling. Neither PKG content nor enzyme activity differed between starved and satiated individuals. We suggest that even though nutrition-related pathways are surely involved in controlling behavioural plasticity, which involves changes in PKG signalling, mediation of satiety itself is independent of PKG.

RevDate: 2019-10-08
CmpDate: 2019-10-08

Lichtenstein L, Lichtenstein M, J Spaethe (2018)

Length of stimulus presentation and visual angle are critical for efficient visual PER conditioning in the restrained honey bee, Apis mellifera.

The Journal of experimental biology, 221(Pt 14): pii:221/14/jeb179622.

Learning visual cues is an essential capability of bees for vital behaviors such as orientation in space and recognition of nest sites, food sources and mating partners. To study learning and memory in bees under controlled conditions, the proboscis extension response (PER) provides a well-established behavioral paradigm. While many studies have used the PER paradigm to test olfactory learning in bees because of its robustness and reproducibility, studies on PER conditioning of visual stimuli are rare. In this study, we designed a new setup to test the learning performance of restrained honey bees and the impact of several parameters: stimulus presentation length, stimulus size (i.e. visual angle) and ambient illumination. Intact honey bee workers could successfully discriminate between two monochromatic lights when the color stimulus was presented for 4, 7 and 10 s before a sugar reward was offered, reaching similar performance levels to those for olfactory conditioning. However, bees did not learn at shorter presentation durations. Similar to free-flying honey bees, harnessed bees were able to associate a visual stimulus with a reward at small visual angles (5 deg) but failed to utilize the chromatic information to discriminate the learned stimulus from a novel color. Finally, ambient light had no effect on acquisition performance. We discuss possible reasons for the distinct differences between olfactory and visual PER conditioning.

RevDate: 2018-11-14
CmpDate: 2018-08-20

Steitz I, Kingwell C, Paxton RJ, et al (2018)

Evolution of Caste-Specific Chemical Profiles in Halictid Bees.

Journal of chemical ecology, 44(9):827-837.

Chemical communication is crucial for the maintenance of colony organization in eusocial insects and chemical signals are known to mediate important aspects of their social life, including the regulation of reproduction. Sociality is therefore hypothesized to be accompanied by an increase in the complexity of chemical communication. However, little is known about the evolution of odor signals at the transition from solitary living to eusociality. Halictid bees are especially suitable models to study this question as they exhibit considerable variability in social behavior. Here we investigated whether the dissimilarities in cuticle chemical signals in females of different castes and life stages reflect the level of social complexity across halictid bee species. Our hypothesis was that species with a higher social behavior ergo obligate eusocial species possess a more distinct chemical profile between castes or female life stages. We analyzed cuticular chemical profiles of foundresses, breeding females and workers of ancestrally solitary species, facultative and obligate eusocial halictid species. We also tested whether social complexity was associated with a higher investment in chemical signals. Our results revealed higher chemical dissimilarity between castes in obligate than in facultative eusocial species, especially regarding macrocyclic lactones, which were the single common compound class overproduced in queens compared with workers. Chemical dissimilarities were independent of differences in ovarian status in obligate eusocial species but were dependent on ovarian status in facultative eusocial species, which we discuss in an evolutionary framework.

RevDate: 2019-09-30
CmpDate: 2019-09-30

Arenas A, F Roces (2018)

Appetitive and aversive learning of plants odors inside different nest compartments by foraging leaf-cutting ants.

Journal of insect physiology, 109:85-92.

Cues inside the nest provide social insect foragers with information about resources currently exploited that may influence their decisions outside. Leaf-cutting ants harvest leaf fragments that are either further processed as substrate for their symbiotic fungus, or disposed of if unsuitable. We investigated whether Acromyrmex ambiguus foragers develop learned preferences for olfactory cues they experienced either in the fungus or in the waste chamber of the nest. Foragers' olfactory preferences were quantified as a choice between sugared papers disks scented with a novel odor and with the odor experienced in one of the nest compartments, before and after odor addition. Odors incorporated in the fungus chamber led to preferences towards paper disks smelling of them. Conversely, odors experienced in the waste chambers led to avoidance of similarly-scented disks. To investigate context-specificity of responses, we quantified learned preferences towards an odor that occurred first in the fungus chamber, and 14 h later in the waste chamber. Foragers initially developed a preference for the odor added in the fungus chamber that turned into avoidance when the same odor solely occurred later in the waste chamber. Avoidance of plants could also be induced in a more natural context, when fresh leaf disks of novel plants, privet or firethorn, were presented in the waste chamber. We conclude that learned acceptance or rejection of suitable plants by foragers depend on the learning context: smells can lead to appetitive learning when present in the fungus garden, or to avoidance learning when they occur at the dump.

RevDate: 2019-09-30
CmpDate: 2019-09-30

Zanni V, Değirmenci L, Annoscia D, et al (2018)

The reduced brood nursing by mite-infested honey bees depends on their accelerated behavioral maturation.

Journal of insect physiology, 109:47-54.

The parasitic mite Varroa destructor is regarded as the most important parasite of honey bees and plays a fundamental role in the decline of bee colonies observed in the last decade in the Northern hemisphere. Parasitization has a number of detrimental effects on bees, including reduced nursing, which can have important impacts on colony balance. In this work we investigated at the individual level the causes of this abnormal behavior and found that the reduced nursing activity in mite-infested workers is associated with impaired learning performance and a series of physiological traits that are typical of foragers, including reduced response to brood pheromone, limited development of hypopharyngeal glands and higher juvenile hormone titre in the haemolymph. Altogether our data confirm the premature transition to foraging already postulated based on previous genomics studies, from a physiological point of view.

RevDate: 2019-06-27
CmpDate: 2019-04-25

Shibasaki S, M Shimada (2018)

Cyclic dominance emerges from the evolution of two inter-linked cooperative behaviours in the social amoeba.

Proceedings. Biological sciences, 285(1881):.

Evolution of cooperation has been one of the most important problems in sociobiology, and many researchers have revealed mechanisms that can facilitate the evolution of cooperation. However, most studies deal only with one cooperative behaviour, even though some organisms perform two or more cooperative behaviours. The social amoeba Dictyostelium discoideum performs two cooperative behaviours in starvation: fruiting body formation and macrocyst formation. Here, we constructed a model that couples these two behaviours, and we found that the two behaviours are maintained because of the emergence of cyclic dominance, although cooperation cannot evolve if only either of the two behaviours is performed. The common chemoattractant cyclic adenosine 3',5'-monophosphate (cAMP) is used in both fruiting body formation and macrocyst formation, providing a biological context for this coupling. Cyclic dominance emerges regardless of the existence of mating types or spatial structure in the model. In addition, cooperation can re-emerge in the population even after it goes extinct. These results indicate that the two cooperative behaviours of the social amoeba are maintained because of the common chemical signal that underlies both fruiting body formation and macrocyst formation. We demonstrate the importance of coupling multiple games when the underlying behaviours are associated with one another.

RevDate: 2019-08-16
CmpDate: 2019-08-16

French AS, K Pfeiffer (2018)

Nonlinearization: naturalistic stimulation and nonlinear dynamic behavior in a spider mechanoreceptor.

Biological cybernetics, 112(5):403-413.

In a previous study, we used linear frequency response analysis to show that naturalistic stimulation of spider primary mechanosensory neurons produced different response dynamics than the commonly used Gaussian random noise. We isolated this difference to the production of action potentials from receptor potential and suggested that the different distribution of frequency components in the naturalistic signal increased the nonlinearity of action potential encoding. Here, we tested the relative contributions of first- and second-order processes to the action potential signal by measuring linear and quadratic coherence functions. Naturalistic stimulation shifted the linear coherence toward lower frequencies, while quadratic coherence was always higher than linear coherence and increased with naturalistic stimulation. In an initial attempt to separate the order of time-dependent and nonlinear processes, we fitted quadratic frequency response functions by two block-structured models consisting of a power-law filter and a static second-order nonlinearity in alternate cascade orders. The same cascade models were then fitted to the original time domain data by conventional numerical analysis algorithms, using a polynomial function as the static nonlinearity. Quadratic models with a linear filter followed by a static nonlinearity were favored over the reverse order, but with weak significance. Polynomial nonlinear functions indicated that rectification is a major nonlinearity. A complete quantitative description of sensory encoding in these primary mechanoreceptors remains elusive but clearly requires quadratic and higher nonlinear operations on the input signal to explain the sensitivity of dynamic behavior to different input signal patterns.

RevDate: 2019-03-13
CmpDate: 2019-03-13

Martin SJ, Correia-Oliveira ME, Shemilt S, et al (2018)

Is the Salivary Gland Associated with Honey Bee Recognition Compounds in Worker Honey Bees (Apis mellifera)?.

Journal of chemical ecology, 44(7-8):650-657.

Cuticular hydrocarbons (CHCs) function as recognition compounds with the best evidence coming from social insects such as ants and honey bees. The major exocrine gland involved in hydrocarbon storage in ants is the post-pharyngeal gland (PPG) in the head. It is still not clearly understood where CHCs are stored in the honey bee. The aim of this study was to investigate the hydrocarbons and esters found in five major worker honey bee (Apis mellifera) exocrine glands, at three different developmental stages (newly emerged, nurse, and forager) using a high temperature GC analysis. We found the hypopharyngeal gland contained no hydrocarbons nor esters, and the thoracic salivary and mandibular glands only contained trace amounts of n-alkanes. However, the cephalic salivary gland (CSG) contained the greatest number and highest quantity of hydrocarbons relative to the five other glands with many of the hydrocarbons also found in the Dufour's gland, but at much lower levels. We discovered a series of oleic acid wax esters that lay beyond the detection of standard GC columns. As a bee's activities changed, as it ages, the types of compounds detected in the CSG also changed. For example, newly emerged bees have predominately C19-C23n-alkanes, alkenes and methyl-branched compounds, whereas the nurses' CSG had predominately C31:1 and C33:1 alkene isomers, which are replaced by a series of oleic acid wax esters in foragers. These changes in the CSG were mirrored by corresponding changes in the adults' CHCs profile. This indicates that the CSG may have a parallel function to the PPG found in ants acting as a major storage gland of CHCs. As the CSG duct opens into the buccal cavity the hydrocarbons can be worked into the comb wax and could help explain the role of comb wax in nestmate recognition experiments.

RevDate: 2018-11-14
CmpDate: 2018-08-20

Villalta I, Abril S, Cerdá X, et al (2018)

Queen Control or Queen Signal in Ants: What Remains of the Controversy 25 Years After Keller and Nonacs' Seminal Paper?.

Journal of chemical ecology, 44(9):805-817.

Ant queen pheromones (QPs) have long been known to affect colony functioning. In many species, QPs affect important reproductive functions such as diploid larvae sexualization and egg-laying by workers, unmated queens (gynes), or other queens. Until the 1990s, these effects were generally viewed to be the result of queen manipulation through the use of coercive or dishonest signals. However, in their seminal 1993 paper, Keller and Nonacs challenged this idea, suggesting that QPs had evolved as honest signals that informed workers and other colony members of the queen's presence and reproductive state. This paper has greatly influenced the study of ant QPs and inspired numerous attempts to identify fertility-related compounds and test their physiological and behavioral effects. In the present article, we review the literature on ant QPs in various contexts and pay special attention to the role of cuticular hydrocarbons (CHCs). Although the controversy generated by Keller and Nonacs' (Anim Behav 45:787-794, 1993) paper is currently less intensively debated, there is still no clear evidence which allows the rejection of the queen control hypothesis in favor of the queen signal hypothesis. We argue that important questions remain regarding the mode of action of QPs, and their targets which may help understanding their evolution.

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