Humans have brought about unprecedented changes to environments worldwide. For many species, behavioral adjustments represent the first response to altered conditions. In this review, we consider the pivotal role that behavior plays in determining the fate of species under human-induced environmental change and highlight key research priorities. In particular, we discuss the importance of behavioral plasticity and whether adaptive plastic responses are sufficient in keeping pace with changing conditions. We then examine the interplay between individual behavioral responses and population processes and consider the many ways in which changes in behavior can affect ecosystem function and stability. Lastly, we turn to the evolutionary consequences of anthropogenic change and consider the impact of altered behaviors on the evolutionary process and whether behavior can facilitate or hinder adaptation to environmental change.
In fish schools the density varies per location and often individuals are sorted according to familiarity and/or body size. High density is considered advantageous for protection against predators and this sorting is believed to be advantageous not only to avoid predators but also for finding food. In this paper, we list a number of mechanisms and we study, with the help of an individual-based model of schooling agents, which spatial patterns may result from them. In our model, schooling is regulated by the following rules: avoiding those that are close by, aligning to those at intermediate distances, and moving towards others further off. Regarding kinship/familiarity, we study patterns that come about when agents actively choose to be close to related agents (i.e., 'active sorting'). Regarding body size, we study what happens when agents merely differ in size but behave according to the usual schooling rules ('size difference model'), when agents choose to be close to those of similar size, and when small agents avoid larger ones ('risk avoidance'). Several spatial configurations result: during 'active sorting' familiar agents group together anywhere in the shoal, but agents of different size group concentrically, whereby the small agents occupy the center and the large ones the periphery ('size difference model' and 'active sorting'). If small agents avoid the risk of being close to large ones, however, small agents end up at the periphery and large ones occupy the center ('risk avoidance'). Spatial configurations are also influenced by the composition of the group, namely the percentage of agents of each type. Furthermore, schools are usually oblong and their density is always greatest near the front. We explain the way in which these patterns emerge and indicate how results of our model may guide the study of spatial patterns in real animals.
Neolamprologus pulcher is a cooperatively breeding cichlid fish, in which helpers stay in their natal territory and help with brood care, territory defense, and maintenance. In this study we investigated helper effects by an experimental group size reduction in the field. After this manipulation, focal helpers in reduced groups tended to feed less, and small helpers visited the breeding shelter significantly more often than same-sized helpers in control groups. No evidence was found that remaining helpers compensated for the removed helpers by increasing territory defense and maintenance behavior. Breeders, however, did show a lower defense rate, possibly caused by an increase in brood care effort. Survival of fry was significantly lower in removal than control groups, which provides the first experimental proof in a natural population of fish that brood care helpers do effectively help. The data suggest that in small, generally younger, helpers, kin selection may be an important evolutionary cause of cooperation. Large helpers, however, who are generally older and less related to the breeders than small helpers are suggested to pay to be allowed to stay in the territory by helping. All group members benefit from group augmentation.
Putty-nosed monkeys, Cercopithecus nictitans stampflii, occur at various sites in West Africa, particularly in the transition zone between rainforest and savannah. The species is sometimes seen in primary rainforest, although at a curiously low density compared with that of other monkey species. We conducted a 24-month field study in the tropical rainforest of Tai National Park, Ivory Coast, and found that putty-nosed monkeys require an ecological niche almost identical to that of the Diana monkeys, Cercopithecus diana diana. Moreover, the niche breadth of putty-nosed monkeys was significantly decreased in the presence of Diana monkeys, suggesting that feeding competition with Diana monkeys kept putty-nosed monkeys from successfully colonizing a rainforest habitat. However, contrary to the interspecies competition hypothesis, groups of both species almost completely overlapped in home ranges and formed near-permanent mixed-species associations, rather than avoiding each other. We hypothesized that Diana monkeys tolerated immigrating putty-nosed monkeys and formed mixed-species groups with them, despite high levels of competition, because of their merit in predation defense. Direct observations and a series of field experiments confirmed that male putty-nosed monkeys play a vital role in defense against crowned eagles, suggesting that putty-nosed monkeys obtain access to feeding trees by offering antipredation benefits to Diana monkeys. We discuss these findings in light of biological market theory.
Guidelines for use of wild mammal species in research are updated from Sikes et al. (2011). These guidelines cover current professional techniques and regulations involving the use of mammals in research and teaching; they also incorporate new resources, procedural summaries, and reporting requirements. Included are details on capturing, marking, housing, and humanely killing wild mammals. It is recommended that Institutional Animal Care and Use Committees (IACUCs), regulatory agencies, and investigators use these guidelines as a resource for protocols involving wild mammals, whether studied in the field or in captivity. These guidelines were prepared and approved by the American Society of Mammalogists (ASM), in consultation with professional veterinarians experienced in wildlife research and IACUCs, whose collective expertise provides a broad and comprehensive understanding of the biology of nondomesticated mammals. The current version of these guidelines and any subsequent modifications are available online on the Animal Care and Use Committee page of the ASM website (http://mammalogy.org/uploads/committee_files/CurrentGuidelines.pdf). Additional resources pertaining to the use of wild animals in research are available at: http://www.mammalsociety.org/committees/animal-care-and-use#tab3. Resumen Los lineamientos para el uso de especies de mamíferos de vida silvestre en la investigación con base en Sikes et al. (2011) se actualizaron. Dichos lineamientos cubren técnicas y regulaciones profesionales actuales que involucran el uso de mamíferos en la investigación y enseñanza; también incorporan recursos nuevos, resúmenes de procedimientos y requisitos para reportes. Se incluyen detalles acerca de captura, marcaje, manutención en cautiverio y eutanasia de mamíferos de vida silvestre. Se recomienda que los comités institucionales de uso y cuidado animal (cifras en inglés: IACUCs), las agencias reguladoras y los investigadores se adhieran a dichos lineamientos como fuente base de protocolos que involucren mamíferos de vida silvestre, ya sea investigaciones de campo o en cautiverio. Dichos lineamientos fueron preparados y aprobados por la ASM, en consulta con profesionales veterinarios experimentados en investigaciones de vida silvestre y IACUCS, de quienes cuya experiencia colectiva provee un entendimiento amplio y exhaustivo de la biología de mamíferos no-domesticados. La presente versión de los lineamientos y modificaciones posteriores están disponibles en línea en la página web de la ASM, bajo Cuidado Animal y Comité de Uso: (http://mammalogy.org/uploads/committee_files/CurrentGuidelines.pdf). Recursos adicionales relacionados con el uso de animales de vida silvestre para la investigación se encuentran disponibles en (http://www.mammalsociety.org/committees/animal-care-and-use#tab3).
Many studies have found that seemingly unconnected behaviors are correlated into behavioral syndromes. These behavioral syndromes may be the consequence of interindividual variation in life-history strategies. Only few studies have investigated the role of behavioral syndromes in cooperatively breeding species, despite the fact that one would expect particular large variation in behavior clue to the wealth of life-history decisions a cooperative breeder faces. In a longitudinal study, we repeatedly tested individuals of the cooperatively breeding cichlid Neolamprologus pulcher for exploration, boldness, and aggression and tested whether these behaviors were sex specific; whether they were interrelated; and whether they were connected to growth and to 2 major life-history decisions, helping, and dispersal. In both sexes, explorative behavior was correlated over time, even though after sexual maturity males increased their exploration rate. In both sexes, exploration, boldness, and aggression correlated when mature, and in females, helping behavior was part of the syndrome. No relationships with growth were detected. Helping and dispersal were related to each other in males, whereas females hardly dispersed. We suggest that the differences in the life histories between males and females (male dispersal vs. female philopatry) lead to the differences in behavioral types observed and also to the differences in the stability of the behavioral syndromes between the sexes. The links between dispersal and helping in males and the behavioral types and helping in females highlight the necessity to study multiple traits to understand the evolution and maintenance of variation in cooperative behavior.
Across a range of disciplines, researchers are becoming increasingly interested in studying the variation in cognitive abilities found within populations. Behavioral ecology is no exception: the pursuit to understand the evolution of cognition has lead to a rapidly expanding literature that uses various tasks to measure individuals' cognitive abilities. While this is an exciting time, we are concerned that without being clearer as to the cognitive abilities under test it will be difficult to design appropriate experiments and the interpretation of the data may be unsound. The aim of this review is 3-fold: 1) to highlight problems with designing tasks for measuring individual variation in cognitive abilities and interpreting their outcomes; 2) to increase awareness that noncognitive factors can cause variation in performance among individuals; and 3) to question the theoretical basis for thinking that performance in any cognitive task should necessarily correlate with a measure of fitness. Our take-home message is that variability in performance in cognitive tasks does not necessarily demonstrate individual variation in cognitive ability, and that we need to both design more stringent cognitive tests and be more cautious in their interpretation.Animals often appear to differ in their cognitive abilities, with some seeming to be more "clever" than others. We highlight problems with designing tasks to measure variation in cognitive abilities and question the idea that those animals that perform better in a specific cognitive task are necessarily going to be the ones that are more successful in life. Are some animals "smarter" than others? We argue that measuring cognitive abilities and comparing them across individual animals is tricky, and that we may need "smarter" experiments to really know.
Anthropogenic (man-made) noise has changed the acoustic environment both on land and underwater and is now recognized as a pollutant of international concern. Increasing numbers of studies are assessing how noise pollution affects animals across a range of scales, from individuals to communities, but the topic receiving the most research attention has been acoustic communication. Although there is now an extensive literature on how signalers might avoid potential masking from anthropogenic noise, the vast majority of the work has been conducted on birds and marine mammals. Fish represent more than half of all vertebrate species, are a valuable and increasingly utilized model taxa for understanding behavior, and provide the primary source of protein for >1 billion people and the principal livelihoods for hunderds of millions. Assessing the impacts of noise on fish is therefore of clear biological, ecological, and societal importance. Here, we begin by indicating why acoustic communication in fish is likely to be impacted by anthropogenic noise. We then use studies from other taxa to outline 5 main ways in which animals can alter their acoustic signaling behavior when there is potential masking due to anthropogenic noise and assess evidence of evolutionary adaptation and behavioral plasticity in response to abiotic and biotic noise sources to consider whether such changes are feasible in fish. Finally, we suggest directions for future study of fish acoustic behavior in this context and highlight why such research may allow important advances in our general understanding of the impact of this global pollutant.
Predators alter prey dynamics by direct killing and through the costs of antipredator responses or risk effects. Antipredator behavior includes proactive responses to long-term variation in risk (e. g., grouping patterns) and reactive responses to short-term variation in risk (e. g., intense vigilance). In a 3-year field study, we measured variation in antipredator responses and the foraging costs of these responses for 5 ungulates (zebra, wildebeest, Grant's gazelle, impala, and giraffe) that comprised more than 90% of the prey community available to the 2 locally dominant predators, lions and spotted hyenas. Using a model-selection approach, we examined how vigilance and group size responded to attributes of the predator, prey, and environment. We found that 1) the strength of antipredator responses was affected by attributes of the predator, prey, and environment in which they met; 2) grouping and vigilance were complementary responses; 3) grouping was a proactive response to the use of dangerous habitats, whereas vigilance was a reactive response to finer cues about predation risk; 4) increased vigilance caused a large reduction in foraging for some species (but not all); and 5) there was no clear relationship between direct predation rates and the foraging costs of antipredator responses. Broadly, our results show that antipredator responses and their costs vary in a complex manner among prey species, the predators they face, and the environment in which they meet.