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Proceedings. Biological Sciences Feb 2019Colour 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...
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.
Topics: Animals; Ants; Color; Learning; Neuronal Plasticity; Neuropil; Random Allocation; Visual Pathways
PubMed: 30963920
DOI: 10.1098/rspb.2018.2813 -
Current Biology : CB Oct 2023Animals form a behavioral decision by evaluating sensory evidence on the background of past experiences and the momentary motivational state. In insects, we still lack...
Animals form a behavioral decision by evaluating sensory evidence on the background of past experiences and the momentary motivational state. In insects, we still lack understanding of how and at which stage of the recurrent sensory-motor pathway behavioral decisions are formed. The mushroom body (MB), a central brain structure in insects and crustaceans, integrates sensory input of different modalities with the internal state, the behavioral state, and external sensory context through a large number of recurrent, mostly neuromodulatory inputs, implicating a functional role for MBs in state-dependent sensory-motor transformation. A number of classical conditioning studies in honeybees and fruit flies have provided accumulated evidence that at its output, the MB encodes the valence of a sensory stimulus with respect to its behavioral relevance. Recent work has extended this notion of valence encoding to the context of innate behaviors. Here, we co-analyzed a defined feeding behavior and simultaneous extracellular single-unit recordings from MB output neurons (MBONs) in the cockroach in response to timed sensory stimulation with odors. We show that clear neuronal responses occurred almost exclusively during behaviorally responded trials. Early MBON responses to the sensory stimulus preceded the feeding behavior and predicted its occurrence or non-occurrence from the single-trial population activity. Our results therefore suggest that at its output, the MB does not merely encode sensory stimulus valence. We hypothesize instead that the MB output represents an integrated signal of internal state, momentary environmental conditions, and experience-dependent memory to encode a behavioral decision.
Topics: Animals; Mushroom Bodies; Neurons; Drosophila; Odorants; Brain; Insecta; Drosophila melanogaster
PubMed: 37657449
DOI: 10.1016/j.cub.2023.08.016 -
Trends in Neurosciences Jun 2023Cataglyphis desert ants are skilled visual navigators. Here, I present a brief overview of multisensory learning and neuronal plasticity in ants, with a particular focus...
Cataglyphis desert ants are skilled visual navigators. Here, I present a brief overview of multisensory learning and neuronal plasticity in ants, with a particular focus on the transition from the dark nest interior to performing first foraging trips. This highlights desert ants as experimental models for studying neuronal mechanisms underlying behavioral development into successful navigators.
Topics: Humans; Animals; Ants; Learning; Neurons; Neuronal Plasticity; Cues
PubMed: 37019813
DOI: 10.1016/j.tins.2023.03.008 -
Philosophical Transactions of the Royal... May 2015This paper introduces a theme issue presenting the latest developments in research on the impacts of sociality on health and fitness. The articles that follow cover...
This paper introduces a theme issue presenting the latest developments in research on the impacts of sociality on health and fitness. The articles that follow cover research on societies ranging from insects to humans. Variation in measures of fitness (i.e. survival and reproduction) has been linked to various aspects of sociality in humans and animals alike, and variability in individual health and condition has been recognized as a key mediator of these relationships. Viewed from a broad evolutionary perspective, the evolutionary transitions from a solitary lifestyle to group living have resulted in several new health-related costs and benefits of sociality. Social transmission of parasites within groups represents a major cost of group living, but some behavioural mechanisms, such as grooming, have evolved repeatedly to reduce this cost. Group living also has created novel costs in terms of altered susceptibility to infectious and non-infectious disease as a result of the unavoidable physiological consequences of social competition and integration, which are partly alleviated by social buffering in some vertebrates. Here, we define the relevant aspects of sociality, summarize their health-related costs and benefits, and discuss possible fitness measures in different study systems. Given the pervasive effects of social factors on health and fitness, we propose a synthesis of existing conceptual approaches in disease ecology, ecological immunology and behavioural neurosciences by adding sociality as a key factor, with the goal to generate a broader framework for organismal integration of health-related research.
Topics: Animals; Behavior, Animal; Biological Evolution; Communicable Diseases; Disease Susceptibility; Genetic Fitness; Humans; Models, Biological; Social Behavior
PubMed: 25870402
DOI: 10.1098/rstb.2014.0116 -
Microbiome Feb 2022Various aspects of sociality can benefit individuals' health. The host social environment and its relative contributions to the host-microbiome relationship have emerged...
BACKGROUND
Various aspects of sociality can benefit individuals' health. The host social environment and its relative contributions to the host-microbiome relationship have emerged as key topics in microbial research. Yet, understanding the mechanisms that lead to structural variation in the social microbiome, the collective microbial metacommunity of an animal's social network, remains difficult since multiple processes operate simultaneously within and among animal social networks. Here, we examined the potential drivers of the convergence of the gut microbiome on multiple scales among and within seven neighbouring groups of wild Verreaux's sifakas (Propithecus verreauxi) - a folivorous primate of Madagascar.
RESULTS
Over four field seasons, we collected 519 faecal samples of 41 animals and determined gut communities via 16S and 18S rRNA gene amplicon analyses. First, we examined whether group members share more similar gut microbiota and if diet, home range overlap, or habitat similarity drive between-group variation in gut communities, accounting for seasonality. Next, we examined within-group variation in gut microbiota by examining the potential effects of social contact rates, male rank, and maternal relatedness. To explore the host intrinsic effects on the gut community structure, we investigated age, sex, faecal glucocorticoid metabolites, and female reproductive state. We found that group members share more similar gut microbiota and differ in alpha diversity, while none of the environmental predictors explained the patterns of between-group variation. Maternal relatedness played an important role in within-group microbial homogeneity and may also explain why adult group members shared the least similar gut microbiota. Also, dominant males differed in their bacterial composition from their group mates, which might be driven by rank-related differences in physiology and scent-marking behaviours. Links to sex, female reproductive state, or faecal glucocorticoid metabolites were not detected.
CONCLUSIONS
Environmental factors define the general set-up of population-specific gut microbiota, but intrinsic and social factors have a stronger impact on gut microbiome variation in this primate species. Video abstract.
Topics: Animals; Bacteria; Female; Gastrointestinal Microbiome; Male; Microbiota; RNA, Ribosomal, 16S; Seasons; Social Behavior
PubMed: 35139921
DOI: 10.1186/s40168-021-01223-6 -
Frontiers in Zoology 2015Comprehensive explanations of behavioral adaptations rarely invoke all levels famously admonished by Niko Tinbergen. The role of developmental processes and plasticity,... (Review)
Review
BACKGROUND
Comprehensive explanations of behavioral adaptations rarely invoke all levels famously admonished by Niko Tinbergen. The role of developmental processes and plasticity, in particular, has often been neglected. In this paper, we combine ecological, physiological and developmental perspectives in developing a hypothesis to account for the evolution of 'the lemur syndrome', a combination of reduced sexual dimorphism, even adult sex ratios, female dominance and mild genital masculinization characterizing group-living species in two families of Malagasy primates.
RESULTS
We review the different components of the lemur syndrome and compare it with similar adaptations reported for other mammals. We find support for the assertion that the lemur syndrome represents a unique set of integrated behavioral, demographic and morphological traits. We combine existing hypotheses about underlying adaptive function and proximate causation by adding a potential developmental mechanism linking maternal stress and filial masculinization, and outline an evolutionary scenario for its canalization.
CONCLUSIONS
We propose a new hypothesis linking ecological, physiological, developmental and evolutionary processes to adumbrate a comprehensive explanation for the evolution of the lemur syndrome, whose assumptions and predictions can guide diverse future research on lemurs. This hypothesis should also encourage students of other behavioral phenomena to consider the potential role of developmental plasticity in evolutionary innovation.
PubMed: 26816515
DOI: 10.1186/1742-9994-12-S1-S15 -
Proceedings. Biological Sciences Feb 2023Social animals are particularly exposed to infectious diseases. Pathogen-driven selection pressures have thus favoured the evolution of behavioural adaptations to...
Social animals are particularly exposed to infectious diseases. Pathogen-driven selection pressures have thus favoured the evolution of behavioural adaptations to decrease transmission risk such as the avoidance of contagious individuals. Yet, such strategies deprive individuals of valuable social interactions, generating a cost-benefit trade-off between pathogen avoidance and social opportunities. Recent studies revealed that hosts differ in these behavioural defences, but the determinants driving such inter-individual variation remain understudied. Using 6 years of behavioural and parasite data on a large natural population of mandrills (), we showed that, when parasite prevalence was high in the population, females avoided grooming their conspecifics' peri-anal region (PAR), where contagious gastro-intestinal parasites accumulate. Females varied, however, in their propensity to avoid this risky body region: across years, some females consistently avoided grooming it, while others did not. Interestingly, hygienic females (i.e. those avoiding the PAR) were less parasitized than non-hygienic females. Finally, age, dominance rank and grooming frequency did not influence a female's hygiene, but both mother-daughter and maternal half-sisters exhibited similar hygienic levels, whereas paternal half-sisters and non-kin dyads did not, suggesting a social transmission of this behaviour. Our study emphasizes that the social inheritance of hygiene may structure behavioural resistance to pathogens in host populations with potential consequences on the dynamics of infectious diseases.
Topics: Animals; Female; Humans; Parasites; Mandrillus; Nuclear Family; Mothers; Social Dominance
PubMed: 36750188
DOI: 10.1098/rspb.2022.2349 -
Journal of the Royal Society, Interface Jan 2015In nature, biofilms are the most common form of bacterial growth. In biofilms, bacteria display coordinated behaviour to perform specific functions. Here, we...
In nature, biofilms are the most common form of bacterial growth. In biofilms, bacteria display coordinated behaviour to perform specific functions. Here, we investigated electrical signalling as a possible driver in biofilm sociobiology. Using a multi-electrode array system that enables high spatio-temporal resolution, we studied the electrical activity in two biofilm-forming strains and one non-biofilm-forming strain. The action potential rates monitored during biofilm-forming bacterial growth exhibited a one-peak maximum with a long tail, corresponding to the highest biofilm development. This peak was not observed for the non-biofilm-forming strain, demonstrating that the intensity of the electrical activity was not linearly related to the bacterial density, but was instead correlated with biofilm formation. Results obtained indicate that the analysis of the spatio-temporal electrical activity of bacteria during biofilm formation can open a new frontier in the study of the emergence of collective microbial behaviour.
Topics: Action Potentials; Bacillus; Bacteria; Bacterial Physiological Phenomena; Biofilms; Electrochemistry; Electrodes; Escherichia coli; Microarray Analysis; Polymers; Pseudomonas; Signal Transduction; Temperature
PubMed: 25392401
DOI: 10.1098/rsif.2014.1036 -
Royal Society Open Science Oct 2023Wild-type Norway rats reciprocate help received in a well-replicated experimental food-giving task, but the criteria to appraise the received help's value are unclear....
Wild-type Norway rats reciprocate help received in a well-replicated experimental food-giving task, but the criteria to appraise the received help's value are unclear. We tested whether quality or quantity of received help is more important when deciding to return help, and whether partner familiarity and own current need affect this evaluation. We experimentally varied recipients of help's hunger state, and familiar or unfamiliar partners provided either higher caloric food (enhanced quantity; carrots) or food higher in protein and fat (enhanced quality; cheese). Reciprocation of received help was our criterion for the rats' value assessment. Familiarity, food type and hunger state interacted and affected help returned by rats. Rats returned less help to familiar partners than to unfamiliar partners. With unfamiliar partners, rats returned more help to partners that had donated preferred food (cheese) than to partners that had donated less preferred food (carrots), and they returned help earlier if they were satiated and had received cheese. With familiar partners, food-deprived rats that had received cheese returned more help than satiated rats that had received carrots. Our results suggest that Norway rats assess the received help's value based on its quality, their current need and partner familiarity before reciprocating received help.
PubMed: 37885980
DOI: 10.1098/rsos.231253 -
Scientific Reports Dec 2022The gut microbiome influences host's immunity, development, and metabolism and participates in the gut-brain axis, thus impacting the health of the host. It is a dynamic...
The gut microbiome influences host's immunity, development, and metabolism and participates in the gut-brain axis, thus impacting the health of the host. It is a dynamic community varying between individuals and within individuals at different time points. Hence, determining the factors causing this variability may elucidate their impact on host's health. However, understanding the drivers of variation has proven difficult particularly as multiple interactions occur simultaneously in the gut microbiome. We investigated the factors shaping the gut microbiome by applying the metacommunity concept where the gut microbiome is considered as a microbial community shaped by the interactions within the community, with the host and microbial communities outside the host, this through a longitudinal study in a wild primate. Focal behavioral data were collected for 1 year in four groups of redfronted lemurs to determine individual social and feeding behaviors. In addition, regular fecal samples were collected to assess bacteria, protozoa, and helminths through marker gene analysis and to measure fecal glucocorticoid metabolite (fGCM) concentrations to investigate the impact of physiological stress on the gut microbiome. Higher consumption of leaves and elevated fGCM concentrations correlated with higher alpha diversity, which also differed among groups. The major drivers of variation in beta diversity were group membership, precipitation and fGCM concentrations. We found positive and negative associations between bacterial genera and almost all studied factors. Correlations between bacterial indicator networks and social networks indicate transmission of bacteria between interacting individuals. We detected that processes occurring inside the gut environment are shaping the gut microbiome. Host associated factors such as, HPA axis, dietary changes, and fluctuations in water availability had a greater impact than interactions within the microbial community. The interplay with microbial communities outside the host also shape the gut microbiome through the exchange of bacteria through social relationships between individuals and the acquisition of microorganisms from environmental water sources.
Topics: Animals; RNA, Ribosomal, 16S; Lemur; Longitudinal Studies; Hypothalamo-Hypophyseal System; Pituitary-Adrenal System; Strepsirhini; Bacteria; Water
PubMed: 36509795
DOI: 10.1038/s41598-022-25733-x