1,721,107 research outputs found
Genetic and Ecological Determinants of Primate Social Systems
No full textKin-selection theory provides an evolutionary framework for the analysis of the effects of genetic relatedness on animal social systems. The aim of this chapter is to review postulated causal relationships between kinship patterns and social systems in non-human primates. In this context it is crucial to distinguish between social organization, i.e., the size and composition of a social unit, and its social structure, i.e., the pattern of social interactions among the members of a social unit. Current theories about the determinants of primate social systems yield predictions about where and why relatives should live together. Results of the available studies of the genetic structure of primate societies indicate deviations in several cases from expected patterns, however. The socioecological model, which has been widely used to analyze and explain relationships among ecological, social and genetic factors, on the one hand, and social structure, on the other hand, has therefore presumably overestimated the effects of kinship on primate social system
Nestmate and non-nestmate recognition: proximal mechanism of template flexibility in ants
No full textSummary chapter 1Over the course of its life, an insect will deploy an extended olfactory perception ability that requires amultitude of sensory receptors, enabling insects to perceive reality beyond the capacity of the humanmind to comprehend. Ants, especially, rely on their olfaction to recognise their nestmates andmaintain the cohesion of the colony. They recognize their nestmates by colony-specific olfactorylabels that individuals store as neural templates in their memory. Learning continuously shapes thenestmate recognition template to keep up with the constant changes in colony labels. This learningis suspected by some author to be rather associative, and by some other not to be. Herewe seek to investigate the mechanism involve in construction of the colony template at the peripheralnervous system responses in term of ORs distribution. We used both behavioural analysis andantennae transcriptomes of Acromyrmex echinatior ants and subjected them to different olfactorytreatments. We show in line of other studies that prolonged exposure to non-nestmate odoursreduces workers aggression towards their label. In our case, the treatment not only affected thebehaviour of the ants but also the expression of their ORs as well as other genes involved in olfactoryand sensory transduction in their antennas. Interestingly, we show that the ORs profile was colonyspecific as much as the label is. Additionally, when we exposed different colonies to the same non-nestmateodour, the initial separation between the olfactory system gene expression, relative tocolonies profiles, disappeared. This indicates that, as their olfactory environments became similar,their ORs profiles also became similar. We looked at the odour exposure effect and realise that as theants’ olfactory environments change, their OR profiles seem to adapt to new sensory realities. Whenants habituate to the odour of another colony, it effectively changes both the nestmate recognitiontemplate and the peripheral nervous system that seems to optimize its sensitivity allowing maybe theants to remain able to perceived relevant cue in their environment.Summary chapter 2Recognition protects biological systems at all scales, from cells to societies. Social insects recognizetheir nestmates by colony-specific olfactory labels that individuals store as neural templates in theirmemory. Throughout an ant's life, learning continuously shapes the nestmate recognition template tokeep up with the constant changes in colony labels. Most explanations for template update rely onnon-associative learning. Ants become habituated to their colony label, their reaction to theomnipresent chemical cues, typical for their own nest, fades. However, habituation cannot explainthe enormous variation in nestmate recognition behaviour. One example would be the neighboursmanagement where some ant species are more aggressive towards neighbouring colonies thantowards unfamiliar colonies (nasty neighbour effect). The distributed model of nestmaterecognition predicts that individual experiences cause variation in recognition ability among individualsand proposes that associative learning of non-nestmate odours leads to this diversity in recognitiontemplates. We already know that social insects can learn by associating an odour cue with a foodreward. Here, we test whether repeated brief encounters of non-nestmate colony odours can leads tolearning, and can explain the nasty neighbour effect observe in Lasius niger ants population. Ourresults demonstrate for the first time that associative learning plays a crucial role in the formation ofboth nestmate and non-nestmate recognition templates, and that the aggression received by an ant actas an unconditioned stimulus that the ant likely associates with the odour label of its enemy. Individualassociative learning can thus explain many phenomena from nasty neighbour effects to agepolyethism. Because different individuals will accumulate different experiences throughout theirlives, their later decisions on whether to accept or reject other individuals will also vary. Group-levelallow more accurate decision than any individual decision alone
Comparative metagenomic and metatranscriptomic analysis of hindgut paunch microbiota in wood- and dung-feeding higher termites
No full textTermites effectively feed on many types of lignocellulose assisted by their gut microbial symbionts. To better understand the microbial decomposition of biomass with varied chemical profiles, it is important to determine whether termites harbor different microbial symbionts with specialized functionalities geared toward different feeding regimens. In this study, we compared the microbiota in the hindgut paunch of Amitermes wheeleri collected from cow dung and Nasutitermes corniger feeding on sound wood by 16S rRNA pyrotag, comparative metagenomic and metatranscriptomic analyses. We found that Firmicutes and Spirochaetes were the most abundant phyla in A. wheeleri, in contrast to N. corniger where Spirochaetes and Fibrobacteres dominated. Despite this community divergence, a convergence was observed for functions essential to termite biology including hydrolytic enzymes, homoacetogenesis and cell motility and chemotaxis. Overrepresented functions in A. wheeleri relative to N. corniger microbiota included hemicellulose breakdown and fixed-nitrogen utilization. By contrast, glycoside hydrolases attacking celluloses and nitrogen fixation genes were overrepresented in N. corniger microbiota. These observations are consistent with dietary differences in carbohydrate composition and nutrient contents, but may also reflect the phylogenetic difference between the hosts
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Receivers limit the prevalence of deception in humans: Evidence from diving behaviour in humans
No full textDeception remains a hotly debated topic in evolutionary and behavioural research. Our understanding of what impedes or facilitates the use and detection of deceptive signals in humans is still largely limited to studies of verbal deception under laboratory conditions. Recent theoretical models of non-human behaviour have suggested that the potential outcome for deceivers and the ability of receivers to discriminate signals can effectively maintain their honesty. In this paper, we empirically test these predictions in a real-world case of human deception, simulation in soccer. In support of theoretical predictions in signalling theory, we show that cost-free deceit by soccer players decreases as the potential outcome for the signaller becomes more costly. We further show that the ability of receivers (referees) to detect deceptive signals may limit the prevalence of deception by soccer players. Our study provides empirical support to recent theoretical models in signalling theory, and identifies conditions that may facilitate human deception and hinder its detection
Do termites avoid carcasses? Behavioral responses depend on the nature of the carcasses.
Full text linkBackgroundUndertaking behavior is a significant adaptation to social life in enclosed nests. Workers are known to remove dead colony members from the nest. Such behavior prevents the spread of pathogens that may be detrimental to a colony. To date, little is known about the ethological aspects of how termites deal with carcasses.Methodology and principal findingsIn this study, we tested the responses to carcasses of four species from different subterranean termite taxa: Coptotermes formosanus Shiraki and Reticulitermes speratus (Kolbe) (lower termites) and Microcerotermes crassus Snyder and Globitermes sulphureus Haviland (higher termites). We also used different types of carcasses (freshly killed, 1-, 3-, and 7-day-old, and oven-killed carcasses) and mutilated nestmates to investigate whether the termites exhibited any behavioral responses that were specific to carcasses in certain conditions. Some behavioral responses were performed specifically on certain types of carcasses or mutilated termites. C. formosanus and R. speratus exhibited the following behaviors: (1) the frequency and time spent in antennating, grooming, and carcass removal of freshly killed, 1-day-old, and oven-killed carcasses were high, but these behaviors decreased as the carcasses aged; (2) the termites repeatedly crawled under the aging carcass piles; and (3) only newly dead termites were consumed as a food source. In contrast, M. crassus and G. sulphureus workers performed relatively few behavioral acts. Our results cast a new light on the previous notion that termites are necrophobic in nature.ConclusionWe conclude that the behavioral response towards carcasses depends largely on the nature of the carcasses and termite species, and the response is more complex than was previously thought. Such behavioral responses likely are associated with the threat posed to the colony by the carcasses and the feeding habits and nesting ecology of a given species
Auswirkungen von sozialem Investment auf die direkte Fitness am Beispiel des Ambrosiakäfers Xyleborinus saxesenii Ratzeburg
No full textVariations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
- …
