Wall-following behavior is the movement along a wall exhibited by various animals. It is a conserved behavior among taxa, from unicellular organisms to humans, prone to selection pressure, and it is energetically cheap since it provides a homogenous trail and can help animals to follow the shortest distance between two points. There are three sets of explanations for this behavior. The first is that it is a defensive behavior meant to lead the animal to shelter or reduce predation risk, and which, at least in vertebrates, is a proxy of anxiety. The second explanation suggests it is an exploratory behavior, helping an animal either to exit an enclosed space or to orient in a novel (unfamiliar) environment, especially when vision is limited. As novel environments often induce stress, these two explanations are not mutually exclusive. Finally, the wall itself may offer some desired biotic or abiotic conditions, such as a higher prey availability moving along it or favorable microclimate conditions. Wall following is a variable behavior, easily affected by the test conditions, such as the test arena size (e.g., more in smaller arenas), shape, and illumination level. Standardization of its measurement is required to facilitate comparison among studies and species. The timing of examination plays a role too: Wall following often changes along development and with aging. Generally, females follow walls more often than do males. Furthermore, certain conditions experienced at a young age affect wall-following later, so the behavioral changes may be long-lasting. Wall following is correlated with a few other behaviors, such as a negative correlation with phototaxis and activity. We end our review by presenting some future research directions, such as examining wall-following behavior in predator-prey systems, examining whether and when wall-following is adaptive, and studying it in the context of urban ecology. Finally, there is a need to examine how common this behavior is in the wild as most studies have been conducted in the lab.
Several factors, such as the susceptibility of different host species to the attacks and particular nutritional requirements of the parasitoids, may influence the patterns of host specificity in host-parasitoid interactions. These patterns are relevant in determining the geographic range of parasitoid species and the impacts on their hosts' population dynamics. In this review, we systematically compile the information available on the use of spider hosts by a group of koinobiont parasitoid wasps, the polysphinctines (Ichneumonidae). These wasps are known by the capacity of their larvae to induce behavioral changes in their hosts, obtaining web structures suitable for the attachment and permanence of the cocoons. We present a host-parasitoid network including data on 173 interactions between 143 spider species and 89 wasp species, discussing the factors involved in the determination of host specificity patterns, such as phylogenetic constraints, host defenses, and the variation in the attack behaviors of wasps during host immobilization. We also investigated the longitudinal and latitudinal patterns of distribution of host-parasitoid interactions within the group. Although some polysphinctines establish associations with numerous hosts, there seems to be a high level of specialization, which becomes evident when we consider the connectivity levels in their interaction network and the limited number of spider families they target. Although traits such as the structural pattern of webs and host size do not appear to be critical factors determining specificity, the identification of stereotyped and specific behaviors adjusted for attacking particular hosts reinforces the hypothesis that specificity within this group of koinobiont manipulative parasitoids is influenced by host's defensive strategies. Our analysis demonstrated that the number of hosts and host diversity per polysphinctine species were not influenced by latitudinal variation, which suggests that these parasitoids have limited tolerance for a wide range of abiotic conditions. Finally, a broad longitudinal distribution of the preferential host species may increase the chances for some of these parasitoids to be in contact with other potential suitable hosts, favoring the use of multiple hosts.
The flexible execution of highly repeated, discrete, and easily recorded tasks makes orb web construction an attractive model for a new generation of general questions concerning complex, flexible behavior by small, apparently simple animals. Accumulated data make it profitable to focus attention on one type of decision that is repeated over and over in each orb: where to attach the sticky spiral to each radius that it crosses. Spiders use at least ten cues to make this decision. Combining this progress with new neurobiological techniques and concepts makes it possible to address new questions concerning higher levels of behavioral organization, including behavioral imprecision (errors), attention and lack of attention, mental maps, open-ended versus rigidly flexible behavioral rules, and the effects of psychoactive drugs. I discuss these and other promising lines for future research. Some data suggest that at least rudimentary higher- level analytical processes occur in orb weavers.
Over 20 years ago, an adaptive, silent male morph called 'flatwing' was discovered in a population of Hawaiian crickets (Teleogryllus oceanicus). Silence protects males against lethal, eavesdropping parasitoid flies (Ormia ochracea). Since then, numerous independent, protective morphs have been discovered, including parallel 'flatwing' mutations, 'small-wing', 'curly-wing', 'rattling-wing', and 'defiled-wing', all of which disrupt structures that generate sound when males rub their wings together. Some crickets also produce a protective, attenuated signal called 'purring'. This cricket-fly arms race is a microcosm of behavioral and evolutionary biology. Here we provide a user's guide to the system. Our research efforts have revealed an important role for behavioral flexibility (i.e., plasticity) in accommodating and accelerating genetic adaptation by enabling both sexes to cope with a changing social environment caused by adaptive signal loss. We describe a unique mode by which behavioral flexibility and novel adaptations are bound together in this system: as each one affects the fitness of the other in a way that facilitates rapid responses to selection, the two co-evolve over time. We advocate for viewing behavior's role in evolution as dynamic rather than static. Our research supports the idea that behavior can change dynamically depending on genetic architecture, demography, and other factors. In addition, the widespread reduction of singing through morphological rather than behavioral change in T. oceanicus pinpoints wing morphology as a hotspot of evolution, and we describe ongoing behavioral and genomic research characterizing this underappreciated mode of adaptation—adaptive breakage—which disrupts previously canalized form-function relationships.
Inbreeding and inbreeding depression are important topics in evolutionary biology and conservation but relatively peripheral to the field of animal behavior. Here, we make a case for why the field of animal behavior should take a greater interest in inbreeding and inbreeding depression. Social interactions, including cooperation, competition, and communication, can have important consequences for our understanding of inbreeding and inbreeding depression. We review studies that examine inbreeding in a social context. This work shows that social interactions can moderate the severity of inbreeding depression by either exacerbating or buffering against the fitness costs of being inbred. Furthermore, social interactions can mediate indirect genetic effects associated with inbreeding—even passing the costs of inbreeding onto outbred individuals. We discuss how a social perspective on inbreeding can advance both our understanding of inbreeding and inbreeding depression and provide an experimental tool to address fundamental problems in the study of animal behavior.
Post-copulatory sexual selection, the post-mating competition between ejaculates, is now widely established as a potent evolutionary driver. However, the competitive environment males face is also not static, potentially altering the fitness outcomes of current vs future matings. Males of many species use cues of their social environment to adjustment their subsequent mating behaviors and ejaculate economics in the face of fluctuating competition. Here we focus on work in Drosophila fruit flies to assess the current understanding of how and why males make these responses. We discuss the progress on understanding the physiological and molecular mechanisms that translate social information into sophisticated plastic responses. We suggest that the potential fitness benefits of flexible reproductive strategies might generate strong selection on cognitive ability as well as on ejaculate investment. We identify avenues for future research and illustrate how studies on Drosophila can serve as a useful model for understanding behavioral plasticity generally.
Mobbing is an important anti-predator behavior where prey harass and attack a predator to lower the immediate and long-term risk posed by predators, warn others, and communicate about the predator’s threat. While this behavior has been of interest to humans since antiquity, and aspects of it have been well researched for the past 50 years, we still know little about its ecology and the evolutionary pressures that gave rise to this ubiquitous anti-predator behavior. In this review, we explore what mobbing is, how it is used, what its functions are thought to be, its use as a proxy for cognition, before providing suggestions for specific future avenues of research necessary to improve our understanding of mobbing in its ecological and evolutionary context.
Research into learning of courtship behavior remains largely confined to birdsong and vocal learning studies. Yet, visually communicated aspects of courtship displays are widespread and prominent, and also deserve consideration. Postural displays, choreographies, and construction of display arenas are all visual signal components mediated by motor activity of the displayer. The goal of this review is to present growing evidence for learning of courtship motor patterns other than song. We tackle two main challenges: we first highlight criteria that can be used to determine whether visual courtship components are learned, and if so, we then assess the type of learning involved. In line with the vocal learning literature, we suggest applying a distinction between usage learning and production learning of motor patterns: usage learning refers to a change in the context in which pre-existing display patterns are used, whereas production learning involves modification in trait structure, i.e. the acquisition of novel display patterns from a model. The effects of imitation, social feedback, and practice are described in detail, drawing on multiple examples from birdsong research. Our goals are to illustrate the learning processes which may affect motor development of courtship signals, to formulate testable predictions for each learning category and related mechanisms, and to suggest possible lines for future research. Although most of the evidence we review here is indirect and not yet conclusive about learning, recent technological advances now provide novel tools to quantify courtship motor patterns, and thus have the potential to produce more direct insights into whether, and how, courtship displays are learned.
The evolution, diversity, and limits of vertebrate cognition are a source of fascination for behavioral biologists, but most work has been confined to mammals and birds, limiting our ability to identify fundamental principles of brain-behavior relationships underlying vertebrate cognition. In contrast to amniotes (reptiles, birds, mammals), amphibian brains differ in complexity and in neural connections in fundamental ways, yet how these differences relate to cognition has rarely been explored. For example, the pallium (i.e., cerebrum) of amphibians has less structural heterogeneity, receives less sensory information, and has relatively few descending connections. One might predict these neurobiological features would limit the complexity of sensory associations, behavioral flexibility, and executive control. Indeed, behavioral studies of amphibians show that response learning, likely controlled by the striatum of the subpallium, predominates over allocentric associations during spatial navigation. Further, while landmark learning is widely evident, complex spatial associations appear less common, perhaps due to a constraint on the complexity of sensory representation in the medial pallium (hippocampus). Finally, while amphibians can flexibly modify previously learned responses through habituation, extinction, and reversal of response learning (e.g., turn left vs. turn right), reversals of visual discriminations are more variable among species. Despite these apparent limitations, at least one amphibian, the parental poison frog Dendrobates auratus, is capable of both spatial learning and higher-order contingency learning, abilities that depend on the hippocampus in mammals. Understanding the neurobiological adaptations that underpin the cognitive abilities of D. auratus will enable us to identify structure-function relationships underlying cognition in amphibians, and in turn, provide critical insight into the evolution of vertebrate cognition.
This chapter contextualizes the dog-human relationship in the dog's origin as a scavenger on the fringes of human settlements over 15,000 years ago. It then reviews the evidence for unique evolved cognitive structures in dogs that could explain their success in a human-dominated world. Failing to find evidence of unique human-like social-cognitive capacities I then review uncontroversial facts of dogs' basic behavioral biology, including reproductive and foraging behavior and, particularly, affiliative and attachment-related behaviors. This leads to consideration of dogs' social behavior, both conspecific and toward other species, especially humans. I draw attention to a seldom-noted apparent contradiction between dogs' stronger affectional bonds toward humans than toward members of their own species. Dogs' social groups also show steeper social hierarchies accompanied by more behaviors indicating formal dominance than do other canid species including wolves. I resolve this contradiction by proposing that dogs' intense sensitivity to social hierarchy contributes to their willingness to accept human leadership. People commonly control resources that dogs need and also unknowingly express behaviors which dogs perceive as formal signs of dominance. This may be what Darwin was referring to when he endorsed the idea that a dog looks on his master as on a god. Whatever the merits of this idea, if it serves to redirect behavioral research on dogs in human society more toward the social interactions of these species in their diverse forms of symbiosis it will have served a useful function.
While considerable evidence exists that extreme climate events such as high temperatures and drought are becoming more common, there is growing recognition that we have limited empirical evidence on how wild animals are able to behaviorally and physiologically adjust to these potentially rapid changes. Despite considerable lab-based research on thermal physiological processes in animals, there is relatively little field-based research on how thermal stress affects physiology and behavior in wild animals. Directly relating physiological state to behavioral change is an important step in understanding the ability of species to adapt to changing climatic conditions and is therefore an important research gap to address during both the current and predicted future rapid changes in climate. Given that the ability of animals to adjust to changing conditions can directly impact their fitness, understanding the behavioral and demographic responses of animal populations to current climate events may be an essential way to determine future population viability. By synthesizing the long-term behavioral research on the pied babbler (Turdoides bicolor), conducted over the last 18 years, we determine the potential impact of climate change through an examination of behavioral responses to social and environmental factors. By combining our detailed behavioral, demographic and physiological research, we use the pied babbler as a model species to highlight the incredible value of (a) long-term behavioral research and (b) studying populations under natural conditions, to help understand the potential impacts of climate change on wild animals.
Many animals have evolved fine-tuned enemy recognition (the ability to discriminate between threat types) and respond to threats based on their particular impact on survival and/or fitness. Birds represent an important and tractable behavioral study system to explore hypotheses of enemy recognition in detail: in addition to predation risk to adult and nest survival, up to 17% of avian species also face reproductive threats from brood parasitism, whereby parasites lay their eggs in other species' nests. While nest predation is detrimental to progeny fitness throughout the reproductive cycle, brood parasitism can carry different costs depending on the host's nest stage and whether the host rejects parasitic eggs or chicks. We conducted a literature review and a formal meta-analysis of studies that conducted model presentation experiments to compare aggression levels of hosts toward brood parasites vs. predators, and synthesized up-to-date findings on such avian enemy recognition patterns. We focused on whether hosts are more aggressive toward brood parasites during the high-cost laying and incubation stages compared to the low-cost nestling stage, whereas responses to nest predators were predicted to be consistently strong or even increasing toward latter nesting stages. We also evaluated whether these front-loaded defenses prior to the brood parasite's access to nests are modulated by hosts' foreign egg ejection responses (accepters vs. rejecters), brood parasitic offspring strategy (nestmate-evictors vs. nest-sharers), and host-brood parasite geographic overlap (sympatry vs. allopatry). As predicted, hosts responded more aggressively toward models of brood parasites during the laying and incubation stages compared to the nestling stage. In turn, host aggression toward nest predators increased in intensity level during the nestling stage. We also found support that host type mediates anti-brood parasitic responses, in that accepters were generally more aggressive to brood parasites than rejecters. We did not find evidence that geographic overlap significantly affected anti-parasitic responses, but we did find differences based on the brood parasite's nestling strategies (evictor vs. non-evictor). These findings indicate that avian hosts of brood parasites make adaptive decisions regarding costly nest defensive behaviors to protect their offspring depending on the type and cost of the threat.
Interactive communication occurs when two or more individuals reciprocally exchange signals. It is widespread and common in humans, non-human animals, and even machines. Territorial songbirds participate in a form of interactive communication known as "countersinging." This chapter reviews research on this model system, with a focus on the last 20 years. It conceptualizes countersinging as a collective behavior that emerges when individuals interact according to rules. I organize research on dyadic countersinging by acoustic domain (time and pattern) and causation (behavioral mechanism, neuro-endocrine mechanism, ontogeny, evolution, and function). Among the topics covered are song overlapping, song rate, variation in song structure, song type switching, soft song, vocal performance, song type matching, countersinging in communication networks, the dawn chorus, and eavesdropping. The chapter ends with a discussion of understudied facets of avian countersinging and recommendations for future research. As the best-studied system of interactive communication in non-human animals, avian countersinging is a valuable model for the evolution of interactive communication.
Many animals live in stable groups, where sexually mature individuals delay dispersal and stay as nonbreeding subordinates, seemingly counter to their own evolutionary interests. Revealing what circumstances drive the evolution of delayed dispersal is central to understanding sociality, family living and cooperative breeding across the animal kingdom, but there is as yet no general consensus about the relative importance of the various ecological and social conditions and the reproductive benefits proposed to drive delayed dispersal. We argue that two components may facilitate further progress in this respect: firstly, full consideration of the various routes that individuals can follow to obtain an independent breeding position. Here, we provide a comprehensive review of these routes: inheritance of a natal territory, budding off part of the natal territory, shifting to a neighboring vacancy, making temporary prospecting trips throughout the population; or permanently leaving to float in search of a breeding position or to stage as subordinate in a non-natal territory. Second, we illustrate that in order to understand delayed dispersal, we need to consider that the fitness consequences of these different routes apply across the lifetime: as subordinate (e.g., benefits of philopatry and indirect fitness); while waiting or searching for a position; and after obtaining a breeding position. Overall, we conclude that by which route and under what circumstances individuals can obtain a breeding position must be considered in order to make more comprehensive inferences about the evolution of delayed dispersal, cooperative breeding and animal sociality as a whole.
Advances in the Study of Behavior was initiated over 40 years ago to serve the increasing number of scientists engaged in the study of animal behavior. This volume makes another important contribution to the development of the field by presenting theoretical ideas and research findings to professionals studying animal behavior and related fields. * Initiated over 40 years ago to serve the increasing number of scientists engaged in the study of animal behavior* Makes another important contribution to the development of the field * Presents theoretical ideas and research to those studying animal behavior and related fields
In internal fertilizers, copulatory behavior and genital morphology are intricately connected because there are many functional and morphological challenges that genitalia must overcome for successful transfer of male gametes into the female reproductive tract. In addition, selective forces can act either on copulatory behavior and genitalia independently or concurrently. However, collecting data on copulatory behavior can be challenging, and there are relatively few studies of genital morphology in Amniotes, which include reptiles, birds, and mammals. As a result, we know little about the relationship between copulation and genitalia in this group. Here we examine copulatory behavior in Amniotes using particularly well-known examples, and add information about the morphology and function of their genitalia to lay a framework for further research on the integration of these traits.
