Abstract Research aimed at understanding the evolution of costly, seemingly altruistic helping behaviour in cooperative birds has strongly focused on a single aspect of helping—offspring provisioning. However, various other activities are also important for successful breeding, most notably nest defence, and emphasis on a single aspect of helping might hamper a full understanding of the evolutionary

Abstract In the context of mate choice, males may vary continuously in their expression of assessment signals, typically reflecting information about variation in mate quality. Similarly, females may exhibit variation in mate preference, which could be due to differences in how individual females perceive signals. The extent to which perception varies across individuals, however, and whether differences

Abstract Social animals exhibit well-organized task allocation among group members. In ants, a large group of eusocial Hymenoptera, the division of labor among workers is maintained by behavioral flexibility, providing robustness against fluctuating environmental conditions. Under stable conditions, worker tasks shift from the inside (e.g., nurses) to the outside (e.g., foragers) of the nest as age

Abstract Emergence of characteristically human traits, including extensive collaboration, prosociality, and cooperative communication, has presumably necessitated evolution toward lower aggression. While empirical studies have provided evidence for evolutionary reduction in human aggression, such as canine teeth reduction in hominins and craniofacial feminization in Homo sapiens, the underlying mechanisms

Abstract Social mammals often live in groups in which a dominance hierarchy is an important determinant of access to mates. In addition to competing individually, males may form coalitions of two or more to attack or intimidate rivals. Coalition formation could be particularly advantageous for adolescent males by helping them compensate for their physical and social immaturity. However, adolescents

Abstract Understanding the causes and consequences of biases in the sex ratio at birth and of adults in species of mammals that have unusual life histories may help us know whether sex ratios are adaptive responses to ecological and evolutionary forces and may be important in conserving endangered species. For example, have sex ratio biases at birth and in adults in species of mammals evolved as an

Abstract Birds living near airports can reduce the noise interference by advancing their dawn chorus timing and avoiding the start of airport operations. Data supporting this finding come from temperate areas, but little is known from tropical environments, where seasonal variation is lower and biodiversity is higher. Here, we investigated whether 15 tropical bird species are able to advance their

Abstract When foraging in a group, individuals adjust their behaviours to the actions of others in order to optimize their pay-offs. While many studies have examined the influence of group composition on behavioural strategies, relatively few have investigated how the presence or absence of conspecifics influences the expression of behaviours during hunting. Another aspect that has received little

Abstract During the last century, the human footprint on natural ecosystems has increased strongly and human-altered habitats such as urban and agricultural areas have extended globally. Despite their negative impacts on biodiversity, these habitats offer unique opportunities to study how native species respond to novel environmental conditions. Here, we studied phenotypic divergence associated with

Abstract Animals create extended phenotypes to adaptively modify and interact with their environment. Animals also respond to changes in the environment by adaptively modifying their behavior or body in a process called phenotypic plasticity. Extended phenotypes might be especially prone to plasticity as they are often the products of behavior. We tested for plasticity in black widow web architecture

Abstract Parental care increases offspring survival, but may impose costs by decreasing adult survival or mating opportunities. Because individuals have limited resources, time allocation and risk decisions are expected to vary according to the care status and threat faced by parents. Herein, we evaluated the sources of mortality of clutches of the glassfrog Hyalinobatrachium cappellei and the importance

Abstract The adaptive nature of invasive species facilitates their survival in conditions that differ markedly from their native range. Behavioral changes in invasive populations are poorly explored but offer a wide potential when combined with physiological traits. For amphibians invading xeric habitats, finding water is important to function optimally and avoid dehydration. The water-finding hypothesis

Abstract Desertion of offspring before its independence by one of the parents is observed in a number of avian species with bi-parental care but reasons for this strategy are not fully understood. This behaviour is particularly intriguing in species where bi-parental care is crucial to raise the brood successfully. Here, we focus on the little auk, Alle alle, a small seabird with intensive bi-parental

Abstract Evaluating the factors influencing the patterns of female dispersal in mammals is critical to understanding its importance for male and female reproductive strategies and the evolution of social systems. In western lowland gorillas, females emigrate from their natal group (natal dispersal) but also disperse between groups multiple times in their life (secondary dispersal). This strategy is

Abstract Females choose to mate with certain males to accrue either genetic or direct benefits, and male sexual attractiveness evolved to advertise those benefits to potential mates. Sexually attractive males are expected to be of higher genetic quality and thus possess greater body condition and perhaps greater disease resistance. Positive covariance between male sexual attractiveness and disease

Abstract Insect parental care strategies are particularly diverse, and prolonged association between parents and offspring may be a key precursor to the evolution of complex social traits. Macroevolutionary patterns remain obscure, however, due to the few rigorous phylogenetic analyses. The subsocial sphecid wasps are a useful group in which to study parental care because of the diverse range of strategies

Abstract Incorporating host behavioral variation into epidemiological models is important for predicting host-pathogen dynamics. Animals living at high densities or with many strong social connections are predicted to have greater risk of acquiring pathogens. Using social network analysis, we tested the hypothesis that variation in the strength of social connections would influence simulated elk (Cervus

Abstract Chimpanzees and humans establish preferences over individuals they may benefit more from through scoring indirect reputation. However, humans prefer prosocial individuals even at their own cost. Giving preference to prosocial reputation over material rewards might have permitted the establishment of cooperative human societies. We tested the evolutionary roots of this propensity: importantly

Abstract Most male frogs produce calls to attract females and repel rivals. The transmission of these calls can be affected by many acoustic and environmental characteristics, which can influence the detection and decoding of the signal by the receiver. Calling-perch height has a strong influence on sound propagation and acoustic spacing with neighboring males, but how frogs optimize their calling

Abstract Telomeres are DNA-protein caps at the ends of chromosomes that have been shown to be associated with male fertility may be heritable, reflect environmental influences and predict life span in some taxa. If heritable, paternal telomere length would be transmitted via sperm in the form of sperm telomere length (STL). We, therefore, investigated STL, sperm number and velocity in the Australian-painted

Abstract Early developmental temperatures influence the physiology and behavior of reptiles, with important consequences for their fitness and survival. For example, many viviparous lizards are cold adapted which may restrict their activity times during the reproductive season, increasing their susceptibility to global warming. However, it is unclear if and how lizards with different reproductive modes

Abstract Despite evidence that organisms are more likely to exhibit their full range of cognitive abilities under conditions found in nature, studies evaluating cognition under such conditions remain rare, particularly in vertebrate species. Here, we conducted an experiment to evaluate problem-solving and motor self-regulation in free-living arboreal lizards, Anolis sagrei, under natural conditions

Abstract Parental investment theory predicts that observed levels of parental care afforded to offspring are set by the benefits (to offspring quality and survival) relative to the costs (to parental survival or future reproduction). Although difficult to document in mammals, there is often substantial individual variation in the amount of parental care within species. We measured the impact of individual

Abstract Various animal species have evolved a sexual communication system with females displaying and males discriminating information about the timing of ovulation through sexual signals. More research is now investigating the potential ovulatory signalling function of female red skin colour in human and non-human primates. However, to date, it is still challenging to draft satisfying hypotheses

Abstract Limited attention constrains predators from engaging in cognitively demanding tasks such as searching for cryptic prey at the same time as remaining vigilant towards threats. Since finite attention can result in negative correlations between foraging and vigilance, the tendency of individual predators to focus attention on searching for cryptic prey may be correlated with other behavioural

Abstract The co-evolutionary arms race between brood parasites and their hosts involves stepwise adaptive changes on the side of the parasites as well as hosts. In response to avian brood parasitism, host females may eject a parasitic egg, bury the parasitized clutch or desert it. After nest desertion, females commonly re-nest and may move further to avoid being parasitized again. Here we tested whether

Abstract Individual recognition (IR) plays an important role in modulating social interactions of several animal species. IR may work at two fundamental levels: at class-level (CIR), if it allows group membership identification (e.g. familiar/unfamiliar), or at individual-level (true IR; TIR), if it allows uniquely recognizing conspecifics. Direct and indirect evidences suggest that many lizards are

Abstract Individual animals across all taxa differ consistently in behaviour, i.e. they show personality traits. This inter-individual variability has significant ecological and evolutionary consequences, since it affects a range of population-level processes. Here, we focus on the selection and recruitment of nursery habitats in temperate fish larvae. The “Sense Acuity and Behavioural Hypothesis”

Abstract Task partitioning allows for efficient coordination of behavior in social insect colonies. Many task allocation studies focus on social insect species with discrete morphological worker subcastes, such as those possessing major and minor workers with strongly differentiated body plans. Much less is known about task partitioning among size-variable workers lacking discrete morphological subcastes

Abstract Dispersal of young from natal home ranges can result in gene flow and increased variation within populations. However, juveniles that remain near kin and form familial groups can accrue indirect fitness benefits. Between 2013 and 2015, we studied families (n = 34) of black-crested titmice (Baeolophus atricristatus) in central Texas to assess factors affecting juvenile dispersal. Our results

Abstract Success in aerial dispersal involves a trade-off between propagule size and dispersal ability, such that reducing weight may increase dispersal capability. Therefore, dispersing propagules such as plant seeds, fungal spores, and insect alates need to settle in new habitats with very limited resources. In termites, the time from alate dispersal to colony foundation is the most critical period

Abstract Distinct behaviours can co-vary within individuals. As such, the magnitude of certain behaviours may be partly predicted by other behaviours, rather than the environment. This can constrain behaviours, potentially reducing behavioural variability. Pre-copulatory sexual cannibalism, the consumption of potential mates before copulation, can lead to females remaining unmated, particularly if

Abstract Production of female gametes is costly; however, there is now wide evidence across different taxa that male ejaculates are also limiting. Thus, multiply mated males may need to partition their ejaculate across successive matings. While more attention has been payed to whether female mating with previously mated males could be sperm limited, there have been fewer studies on depletion of other

Abstract Wind, a major source of environmental noise, forces invertebrates that communicate with plant-borne vibrations to adjust their signaling when communicating in windy conditions. However, the strategies that animals use to reduce the impact of wind noise on communication are not well studied. We investigated the effects of wind on the production of tremulatory signals in the neotropical katydid

Abstract Many species of bats live in dynamic associations in which individuals aggregate or split into smaller or larger groups, moving between roost sites, but factors influencing group size and roost switching decisions in bats living in fission-fusion societies are poorly understood. To test the extent to which fission-fusion dynamics are species-specific and shaped by environmental factors, we

Abstract While constrained by endogenous rhythms, morphology and ecology, animals may still exhibit flexible activity patterns in response to risk. Temporal avoidance of interspecific aggression can enable access to resources without spatial exclusion. Apex predators, including humans, can affect mesopredator activity patterns. Human context might also modify temporal interactions between predators

Abstract Synchronous hatching is widespread among oviparous taxa. However, the adaptive significance of this phenomenon is unclear, as are the cues mediating hatching synchrony. We took a comparative approach and experimentally tested for synchronous hatching in two freshwater turtles with different life histories (Apalone spinifera and Graptemys geographica). We also aimed to disentangle the cues

Abstract To maintain group cohesion while coordinating group movements, individuals might use signals to advertise the location of a route, their intention to initiate movements, or their position at a given time. In highly mobile animals, the latter is often accomplished through contact calls that are emitted at different rates by group members. Here, we describe and quantify intra- and intergroup

Abstract According to the dear enemy phenomenon, territory owners decrease costs of ownership by decreasing aggression toward neighbors once territory boundaries have been established. To maintain this cooperation, when territorial neighbors are caught in the act of “cheating” by failing to respect territory boundaries, they should be “challenged” via increased aggression. Most studies examining this

Abstract We studied female phonotaxis in gray treefrogs to learn how male aggressive calling influences female choice of a mate from the perspective of the aggressive signaler and his male target. Although aggressive calls on their own attracted some females, when allowed to choose, all females preferred advertisement calls to aggressive calls. We wanted to ascertain also whether such calls could reduce

Abstract In many species, individuals contest resources using specialized morphologies to overpower rivals, hereafter referred to as weapons. Despite their importance in fights, little is known about the selective forces affecting weapon evolution. This may be particularly important to understand why weapons are highly variable among species. Due to their role during fighting, we expect that whenever

Abstract Shared behavioural traits result from the interaction of two or more individuals, making it difficult to discern which individual is in control of the behaviour of interest. Especially in the case of shared reproductive traits such as mating duration or mate guarding duration is this an important issue to resolve, because these are potentially closely connected to fitness and are likely to

Abstract Food-caching animals can gain nutritional advantages by buffering seasonality in food availability, especially during times of scarcity. The wolverine (Gulo gulo) is a facultative predator that occupies environments of low productivity. As an adaptation to fluctuating food availability, wolverines cache perishable food in snow, boulders, and bogs for short- and long-term storage. We studied

Abstract Previous research has shown that competition, familiarity, diet, and relatedness can all influence aggregation patterns in garter snakes. We controlled for these factors and examined social aggregation patterns in juvenile Eastern garter snakes (Thamnophis sirtalis sirtalis). We assayed snakes individually for consistent individual differences in boldness and sociability. We then placed snakes

Abstract Social interactions among conspecifics can have marked effects on individual physiology, especially through their modulation of the stress axis by affecting the production of adrenal glucocorticoids (GCs). Previous research has focused on how individual GC levels may be influenced by social status, but few studies have considered how the balance between positive (e.g. cooperation) and negative

Abstract The frequency and unpredictability of predator attacks can substantially influence vigilance patterns in prey animals. However, the lack of control over predator behavior hampers our understanding of the effect of predator attack patterns on vigilance. To circumvent this limitation, I developed a virtual experiment in which the behavior of the (virtual) predator was under full control of the

Abstract Birds communicate their motivation and willingness to escalate a territorial conflict with a variety of agonistic signals. One of these, song-type switching, has been suggested to be a conventional signal in male–male interactions. However, this behavior does not show a consistent pattern across species. In this study, we asked whether variation in song-switching rate carries a message for

Abstract Living in groups is widespread and multiple attributes can affect grouping decisions. In several taxa, social familiarity mediates group formation and maintenance, while phenotypic homogeneity within groups may enhance antipredator responses by exploiting the confusion effect. Although familiarity and homogeneity are crucial attributes for social life, little is known about their relative

Abstract Conspicuous coloration in animals has many possible functions including signaling to conspecifics, or predator deterrence through confusion, intimidation, and duping; the last includes flash behavior where predators are deceived into looking for conspicuous cues exhibited in flight but that are hidden when the animal comes to rest. In an effort to see if flash behavior occurs in mammals, we

Abstract Most of our knowledge about the function, evolution, neurobiology and ontogeny of complex vocalizations in birds comes from previous work on male song. However, the recent increase in focus on female bird song over the last few decades has helped bridge that gap in our knowledge and has vastly changed our understanding of the function, phylogeny and evolution of bird song. Here we present

Abstract In many group-living animal species, interactions take place in changing social environments, increasing the information processing necessary to optimize social decision-making. Communities with different levels of spatial and temporal cohesion should differ in the predictability of association patterns. While the focus in this context has been on primate species with high fission-fusion dynamics

Abstract The evolution and function of female trait exaggeration in species with traditional sex roles are poorly understood. Competition for social and ecological resources, rather than mating opportunities, may be a key selection pressure in females of socially monogamous species. Moreover, such pre-existing resource competition-selected traits (armaments) may become the object of mating preferences

Abstract Female orangutans exhibit natal philopatry, living in stable home ranges that overlap with those of their maternal relatives. Using data collected from 2003 to 2017 at Tuanan in Central Kalimantan, Indonesia, we take a longitudinal approach to better understand the mechanisms of female philopatry and the factors that influence the home range establishment process of young female orangutans

Abstract There is an ongoing debate about whether simultaneous hermaphrodites capable of selfing should prefer selfing over outcrossing or vice versa. While many theoretical models predict a transmission advantage for alleles that favour selfing, empirical studies often reveal low selfing rates. Despite these considerations, the underlying mechanisms that determine reproductive strategies in simultaneously

Abstract Animals inhabiting montane gradients experience varying winter climates that may result in differential selection on survival-related traits. Higher elevations in temperate climates are characterized by harsher winters with greater and longer-lasting snow cover compared to lower elevations, potentially leading to stronger selection for traits that improve fitness under these harsher conditions

Abstract Many species of birds produce distinct calls when mobbing predators. These calls often recruit nearby conspecifics and heterospecifics to help drive the predators away. In some species, such as members of the family Paridae, mobbing calls are composed of multiple elements that seem to follow a characteristic order. Previous work in parids demonstrated that note ordering influences both the

Abstract Avian plumage colors and ornaments are excellent models to study the endocrine mechanisms linking sexually selected traits and individual parameters of quality and condition. Insulin-like growth factor 1 (IGF-1) is an evolutionarily highly conserved peptide hormone. Its regulatory role in cell proliferation and differentiation and its high sensitivity to the nutritional state of individuals

Abstract In many species, individuals prefer mates that are genetically dissimilar at the major histocompatibility complex (MHC), likely because it improves offspring resistance to pathogens. Here, we provide the first characterization of the MHC class II peptide binding region in bluegill (Lepomis macrochirus) and examine its effect on mating patterns. We captured female and male bluegill during spawning

Abstract The death of the queen can lead to behavioral changes in workers of eusocial bees that alter their longevity. Here, we investigated the behavior and longevity of workers in colonies of the neotropical stingless bee Scaptotrigona aff. postica in the absence of a mated queen. Eight colonies, four being queenright, and four with their physogastric queens removed (queenless), were used in experiments

Abstract In theory, a male should change the allocation of fighting and mating efforts in relation to his age. Thus, the consequences of sexual selection may be complicated by changes in the male resource allocation due to aging. However, previous studies have focused on changes in female mate choice and male-male competition with aging separately, and the impact of aging on the relationship between