Competing neighbors: light perception and root function

The literature reveals opposing views regarding the importance of intrinsic population regulation in mammals. Different models have been proposed; adding importance to contrasting life histories, body sizes and social interactions. Here we evaluate current theory based on results from two Scandinavian projects studying two ecologically different mammal species with contrasting body sizes and life history traits: the root vole Microtus oeconomus and the brown bear Ursus arctos. We emphasize four inter-linked behavioral aspects—territoriality, dispersal, social inhibition of breeding, and infanticide—that together form a density-dependent syndrome with potentially regulatory effects on population growth. We show that the two species are similar in all four behaviors and thus the overall regulatory syndrome. Females form matrilineal assemblages, female natal dispersal is negatively density dependent and breeding is suppressed in philopatric young females. In both species, male turnover due to extrinsic mortality agents cause infanticide with negative effects on population growth. The sex-biased and density-dependent dispersal patterns promote the formation of matrilineal clusters which, in turn, leads to reproductive suppression with potentially regulatory effects. Hence, we show that intrinsic population regulation interacting with extrinsic mortality agents may occur irrespective of taxon, life history and body size. Our review stresses the significance of a mechanistic approach to understanding population ecology. We also show that experimental model populations are useful to elucidate natural populations of other species with similar social systems. In particular, such experiments should be combined with methodical innovations that may unravel the effects of cryptic intrinsic mechanisms such as infanticide.     

Integration of field and captive studies for understanding the behavioral ecology of the squirrel monkey (Saimiri sp.)

Captive and field studies both provide valuable and complementary information that lead to a better understanding of a species' behavioral ecology. Here, we review studies from wild, captive, and semi-free ranging populations of squirrel monkeys (Saimiri sp.), in order to (a) provide a more current (1985-2010) review of Saimiri behavioral ecology and (b) illustrate that integrating data collected in a variety of settings is an effective approach to addressing ecological questions in primates. Captive environments, such as zoological facilities and research colonies, can be advantageous to researchers by allowing longitudinal studies of behavior and reproduction, as well as providing opportunities for gathering data on life history, because physiological and life history data are known for individual animals. Studies of field populations can provide contextual information regarding the adaptive nature of behaviors that are studied in captivity. Squirrel monkeys are small, neotropical primates that have extensively been used in captive research. As the last in-depth review of Saimiri biology was published in 1985 [Rosenblum & Coe, The squirrel monkey. New York: Academic Press], we review studies since conducted on Saimiri ecology, life history, social behavior, reproduction, and conservation. Our review indicates that there is much variation in socioecology and life history traits between Saimiri species and, surprisingly, also between populations of the same species studied at different locales. In addition, much is known about squirrel monkey reproductive physiology, basic ecology, and vocal communication, but data are still lacking in the fields of life history and some adaptive components and social behavior. In particular, longitudinal studies in the field would be particularly relevant for a genus with a slow life history such as Saimiri. Finally, few data (captive or wild) are available on S. ustus and S. vanzolinii, though at least one of these species is threatened.     

Ecology and evolution of long-lived semelparous plants

One of the more dramatic life histories in the natural world is that characterized by a single, massive, fatal reproductive episode ('semelparity'). A wealth of increasingly sophisticated theoretical models on differential life history evolution have been produced over the last two decades. In recent years, empirical studies of the ecology of semelparous plants (and their iteroparous relatives) have begun to address many aspects of the biology of these species, and to test the assumptions and predictions of theoretical models. Semelparity in long-lived plants is one of the few natural phenomena that has yielded specific quantitative tests of mathematical evolutionary theory.     

Towards a behavioral ecology of ecological landscapes

Recent developments in landscape-level ecological modeling rest upon poorly understood behavioral phenomena. Surprisingly, these phenomena include animal movement and habitat selection, two areas with a long history of study in behavioral ecology. A major problem in applying traditional behavioral ecology to landscape-level ecological problems is that ecologists and behaviorists work at very different spatial scales. Thus a behavioral ecology of ecological landscapes would strive to overcome this inopportune differential in spatial scales. Such a landscape-conscious behavioral undertaking would not only establish more firmly the link between behavior and ecological systems, but also catalyze the study of basic biological phenomena of Interest to behaviorists and ecologists alike.     

Primates got personality,too: Toward an integrative primatology of consistent individual differences in behavior

In recent years, research on animal personality has exploded within the field of behavioral ecology. Consistent individual differences in behavior exist in a wide range of species, and these differences can have fitness consequences and influence several aspects of a species' ecology. In comparison to studies of other animals, however, there has been relatively little research on the behavioral ecology of primate personality. This is surprising given the large body of research within psychology and biomedicine showing that primate personality traits are heritable and linked to health and life history outcomes. In this article, I bring together theoretical perspectives on the ecology and evolution of animal personality with an integrative review of what we know about primate personality from studies conducted on captive, free‐ranging, and wild primates. Incorporating frameworks that emphasize consistency in behavior into primate behavioral ecology research holds promise for improving our understanding of primate behavioral evolution.     

Social behavior and pheromonal communication in reptiles

The role of pheromones in orchestrating social behaviors in reptiles is reviewed. Although all reptile orders are examined, the vast majority of the literature has dealt only with squamates, primarily snakes and lizards. The literature is surprisingly large, but most studies have explored relatively few behaviors. The evolution of chemical signaling in reptiles is discussed along with behaviors governed by pheromones including conspecific trailing, male-male agonistic interactions, sex recognition and sex pheromones, and reptilian predator recognition. Nonreptilian prey recognition by chemical cues was not reviewed. The recent literature has focused on two model systems where extensive chemical ecology studies have been conducted: the reproductive ecology of garter snakes and the behavioral ecology of Iberian lacertid lizards. In these two systems, enough is known about the chemical constituents that mediate behaviors to explore the evolution of chemical signaling mechanisms that affect life history patterns. In addition, these models illuminate natural and sexual selection processes which have lead to complex chemical signals whose different components and concentrations provide essential information about individuals to conspecifics. Reptiles provide excellent candidates for further studies in this regard not only in squamates, but also in the orders where little experimental work has been conducted to date.     

The long and winding road of evolutionary demography: preface

Fitness can be calculated using demographic parameters such as survival and fecundity, which are normally used to examine population dynamics in ecology. This concept is at the heart of Darwin's thinking on natural selection. Natural selection optimizes survival and fertility schedules through differential fitness, and these optimal schedules drive changes in population dynamics. Therefore, there must exist an interaction between ecology and evolution. One of the disciplines that focus on the interaction is "Evolutionary demography". It uses age- or stage-specific demographic parameters throughout the whole life history to explore the evolution of life histories. Data throughout the life history of a species is indispensable to study evolutionary demography. To this end, two large-scale databases of plant and animal life history are now available online, the COMPADRE Plant Matrix Database and the COMADRE Animal Matrix Database. We are now in a revolutionary era in the demographic research of plant and animal populations (including human populations). Many skills and approaches are needed to answer questions on evolutionary demography including bodies of theory and analytical toolkits. This special issue covers a wide array of subjects: (1) Demographic analysis of populations (including human populations) from the point of view of evolutionary ecology, (2) Meta-analysis using big databases of populations, (3) Eco-evolutionary studies at the population and/or community level and (4) Theoretical studies and the development of mathematical models of life history evolution. 14 collected papers are published to answer a variety of questions using original ideas, new tools, and big data.     

A guide to practical babooning: Historical,social, and cognitive contingency

As ecologically adaptable animals, baboons are distributed widely across Africa, and display a variety of morphological and behavioral differences that reflect both local ecology and a complex evolutionary history. As long‐lived, slowly reproducing animals, baboons face numerous ecological challenges to survival and successful reproduction. As group‐living animals, the social world presents an equally diverse array of challenges that require the negotiation of individual needs within the constraints imposed by others. Understanding how all these facets of baboon evolutionary history, life history, ecology, sociality, and cognition fit together is an enormous but engaging challenge, and despite one hundred years of study, it is clear there is a still much to learn about the various natural histories of baboons. What also is clear, however, is that an appreciation of contingency holds the key to understanding all these facets of baboon evolution and behavior. In what follows, I hope to illustrate exactly what I mean by this, highlighting along the way that history is not to be ignored, variability is information and not merely “noise”, and that behavioral and cognitive complexity can be two very different things.     

Differences in boldness are repeatable and heritable in a long‐lived marine predator

Animal personalities, composed of axes of consistent individual behaviors, are widely reported and can have important fitness consequences. However, despite theoretical predictions that life‐history trade‐offs may cause and maintain personality differences, our understanding of the evolutionary ecology of personality remains poor, especially in long‐lived species where trade‐offs and senescence have been shown to be stronger. Furthermore, although much theoretical and empirical work assumes selection shapes variation in personalities, studies exploring the genetic underpinnings of personality traits are rare. Here we study one standard axis of personality, the shy–bold continuum, in a long‐lived marine species, the wandering albatross from Possession Island, Crozet, by measuring the behavioral response to a human approach. Using generalized linear mixed models in a Bayesian framework, we show that boldness is highly repeatable and heritable. We also find strong differences in boldness between breeding colonies, which vary in size and density, suggesting birds are shyer in more dense colonies. These results demonstrate that in this seabird population, boldness is both heritable and repeatable and highlights the potential for ecological and evolutionary processes to shape personality traits in species with varying life‐history strategies.     

Next-Generation Individual-Based Models Integrate Biodiversity and Ecosystems: Yes We Can,and Yes We Must

Ecosystem and community ecology have evolved along different pathways, with little overlap. However, to meet societal demands for predicting changes in ecosystem services, the functional and structural view dominating these two branches of ecology, respectively, must be integrated. Biodiversity–ecosystem function research has addressed this integration for two decades, but full integration that makes predictions relevant to practical problems is still lacking. We argue that full integration requires going, in both branches, deeper by taking into account individual organisms and the evolutionary and physico-chemical principles that drive their behavior. Individual-based models are a major tool for this integration. They have matured by using individual-level mechanism to replace the demographic thinking which dominates classical theoretical ecology. Existing individual-based ecosystem models already have proven useful both for theory and application. Still, next-generation individual-based models will increasingly use standardized and re-usable submodels to represent behaviors and mechanisms such as growth, uptake of nutrients, foraging, and home range behavior. The strategy of pattern-oriented modeling then helps make such ecosystem models structurally realistic by developing theory for individual behaviors just detailed enough to reproduce and explain patterns observed at the system level. Next-generation ecosystem scientists should include the individual-based approach in their toolkit and focus on addressing real systems because theory development and solving applied problems go hand-in-hand in individual-based ecology.     

Modelling spatial dynamics of fish

Our ability to model spatial distributions of fish populations is reviewed by describing the available modelling tools. Ultimate models of the individual's motivation for behavioural decisions are derived from evolutionary ecology. Mechanistic models for how fish sense and may respond to their surroundings are presented for vision, olfaction, hearing, the lateral line and other sensory organs. Models for learning and memory are presented, based both upon evolutionary optimization premises and upon neurological information processing and decision making. Functional tools for modelling behaviour and life histories can be categorized as belonging to an optimization or an adaptation approach. Among optimization tools, optimal foraging theory, life history theory, ideal free distribution, game theory and stochastic dynamic programming are presented. Among adaptation tools, genetic algorithms and the combination with artificial neural networks are described. The review advocates the combination of evolutionary and neurological approaches to modelling spatial dynamics of fish.     

Is there a role for culture in human behavioral ecology?

Most research in human behavioral ecology has been acultural, which raises the question of how best to incorporate the concept of culture into this approach. A necessary step in this direction is to pare the culture concept down to its ideational elements, excluding behavior and its material products (Durham 1991; Geertz 1973; Keesing 1974). The cultural and reproductive success hypothesis, though empirically successful (Irons 1993), is not a model for all of culture because of widespread discrepancies between behavior and culture to which it does not call attention. Cultural transmission models are also weakened by such discrepancies, but, more importantly, such models are most relevant to phenomena different from those central to human behavioral ecology. A better way to incorporate culture into human behavioral ecology is to see it as the context of human action and as a tool people use in social manipulation. The study of signal systems is a key to an understanding of social manipulation and to the incorporation of culture into human behavioral ecology. Examples of the manipulation of culture for reproductive benefit include Yanomamö kin term manipulation (Chagnon 1988), incest rules (Thornhill 1990, 1991), and the derogation of sexual competitors (Buss and Dedden 1990). The human behavioral ecological study of social manipulation in cultural contexts needs to be expanded. Two phenomena that might shed light on such manipulation are the Rashomon effect and the audience effect.     

Life‐history strategy and behavioral type: risk‐tolerance reflects growth rate and energy allocation in ant colonies

Despite the recent interest in animal personality and behavioral syndromes, there is a paucity of explanations for why distinct behavioral traits should evolve to correlate. We investigate whether such correlations across apparently distinct behavioral traits may be explained by variation in life history strategy among individual ant colonies. Life history theory predicts that the way in which individuals allocate energy towards somatic maintenance or reproduction drives several distinct traits in physiology, morphology, and energy use; it also predicts that an individual's willingness to engage in risky behaviors should depend on reproductive strategy. We use Temnothorax ants, which have been shown to exhibit ‘personalities’ and a syndrome that may reflect risk tolerance at the colony level. We measure colonies' relative investment in growth rate (new workers produced) compared to reproductive effort (males and queens produced). Comparing sterile worker production to reproductive alate production provides a direct measure of how colonies are investing their energy, analogous to investment in growth versus reproduction in a unitary organism. Consistently with this idea, we found that behavioral type of ant colonies was associated with their life history strategy: risk‐tolerant colonies grew faster and invested more in reproduction, whereas risk‐averse colonies had lower growth rate but invested relatively more in workers. This provides evidence that behavioral syndromes can be a consequence of life‐history strategy variation, linking the two fields and supporting the use of an integrative approach.     

Habitat‐driven life history variation in an amphibian metapopulation

Life‐history theory states that, during the lifetime of an individual, resources are allocated to either somatic maintenance or reproduction. Resource allocation tradeoffs determine the evolution and ecology of life‐history strategies and determine an organisms’ position along the fast–slow continuum. Theory predicts that environmental stochasticity is an important driver of resource allocation and therefore life‐history evolution. Highly stochastic environments are expected to increase uncertainty in reproductive success and select for iteroparity and a slowing down of the life history. To date, most empirical studies have used comparisons among species to examine these theoretical predictions. By contrast, few have investigated how environmental stochasticity affects life‐history strategies at the intraspecific level. In this study, we examined how variation in breeding site stochasticity (among‐year variability in pond volume and hydroperiod) promotes the co‐occurrence of different life‐history strategies in a spatially structured population, and determines life‐history position along the fast–slow continuum in the yellow‐bellied toad Bombina variegata. We collected mark–recapture data from a metapopulation and used multievent capture–recapture models to estimate survival, recruitment and breeding probabilities. We found higher survival and longer lifespans in populations inhabiting variable sites compared to those breeding in stable ones. In addition, probabilities of recruitment and skipping a breeding event were higher in variable sites. The temporal variance of survival and recruitment probabilities, as well as the probability to skip breeding, was higher in variable sites. Taken together, these findings indicate that populations breeding in variable sites experienced a slowing down of the life‐history. Our study thus revealed similarities in the macroevolutionary and microevolutionary processes shaping life‐history evolution.     

Cost of reproduction and covariation of life history traits in birds

Evolution of life history traits can be studied at two different levels: (1) current selection processes, including trade-offs in life history traits in natural populations as revealed by observations or, preferably, exieriments; and (2) patterns of variation in life history traits with each other and with ecology among extant species. Selection is not evolution, but selection pressures must have caused evolutionary change and led to current patterns of life history traits. These problems are exemplified by recent research on clutch size in birds.     

Tests of density dependence using indices of relative abundance in a deer population

A major question in animal ecology is explaining the causes of population fluctuations. Consensus about the most reliable method to detect density dependence (DD) or environmental effects from time‐series data, however, has not yet been achieved. Times series analyses have been used with indices of relative abundance in numerous studies, although these indices are rarely validated. Here, we used three different time series of relative abundance (number of deer seen per hunter per day, hunting success and proportion of males in the harvest) to explore direct and delayed DD in a white‐tailed deer Odocoileus virginianus population on Anticosti Island, Québec, Canada. Three mathematical approaches were tested: linear models, autoregressive (AR) models, and total DD in life history. Tests of DD using different indices of abundance on the same population should lead to similar results if all indices exhibit similar behaviour. Indices of relative abundance correlated with each other, although sometimes weakly, such that we obtained similar DD estimates with each index using detrended non‐stationary series. In most time series, linear regression of N_t?1 and N_t and AR models did not detect DD, while we obtained strong evidence for DD from the life‐history approach. This meant that contrasting conclusions about the role of density dependence within this population were reached depending on which method was used. We conclude that the method that incorporates most biological realism, the life‐history approach, provided a different result than classical interpretation of autoregressive coefficients. Only the life‐history interpretation supported our a priori belief that density dependence operating through competition for food regulates the Anticosti deer population. Phenomenological analysis aiming to investigate changes in abundance should be carefully conducted as the use of inappropriate indices or methods could lead to inappropriate conclusions or management strategies. Preferably, the method used should match the time scale of the population sampling regime and species life history.     

Genetic confounding of the relationship between father absence and age at menarche

Research in evolutionary psychology, and life history theory in particular, has yielded important insights into the developmental processes that underpin variation in growth, psychological functioning, and behavioral outcomes across individuals. Yet, there are methodological concerns that limit the ability to draw causal inferences about human development and psychological functioning within a life history framework. The current study used a simulation-based modeling approach to estimate the degree of genetic confounding in tests of a well-researched life history hypothesis: that father absence (X) is associated with earlier age at menarche (Y). The results demonstrate that the genetic correlation between X and Y can confound the phenotypic association between the two variables, even if the genetic correlation is small—suggesting that failure to control for the genetic correlation between X and Y could produce a spurious phenotypic correlation. We discuss the implications of these results for research on human life history, and highlight the utility of incorporating genetically sensitive tests into future life history research.     

Spatial Scale,Means and Gradients of Hydrographic Variables Define Pelagic Seascapes of Bluefin and Bullet Tuna Spawning Distribution

Seascape ecology is an emerging discipline focused on understanding how features of the marine habitat influence the spatial distribution of marine species. However, there is still a gap in the development of concepts and techniques for its application in the marine pelagic realm, where there are no clear boundaries delimitating habitats. Here we demonstrate that pelagic seascape metrics defined as a combination of hydrographic variables and their spatial gradients calculated at an appropriate spatial scale, improve our ability to model pelagic fish distribution. We apply the analysis to study the spawning locations of two tuna species: Atlantic bluefin and bullet tuna. These two species represent a gradient in life history strategies. Bluefin tuna has a large body size and is a long-distant migrant, while bullet tuna has a small body size and lives year-round in coastal waters within the Mediterranean Sea. The results show that the models performance incorporating the proposed seascape metrics increases significantly when compared with models that do not consider these metrics. This improvement is more important for Atlantic bluefin, whose spawning ecology is dependent on the local oceanographic scenario, than it is for bullet tuna, which is less influenced by the hydrographic conditions. Our study advances our understanding of how species perceive their habitat and confirms that the spatial scale at which the seascape metrics provide information is related to the spawning ecology and life history strategy of each species.     

Ecology of gorillas and its relation to female transfer in mountain gorillas

Understanding the principles that underly primate social evolution depends on integrated analysis of data on behavioral ecology, demography, life history tactics, and social organization. In this paper, data on the behavioral ecology of gorillas are reviewed and comparisons made among the three subspecies. Gorillas are selective feeders; and, their patterns of food choice are consistent with models of feeding by large generalist herbivores. They rely heavily on terrestrial herbaceous vegetation, which provides an abundant supply of densely distributed food. Availability of this food varies little in space and time; and, gorilla foraging activity can maintain its productivity. The level of frugivory and the extent of seasonal variation in diet and habitat use vary among and within populations. Low variability in food distribution patterns makes cooperative defense of foraging areas not worthwhile; but, it also means that ecological costs associated with gregariousness are low. However, demographic and life history data on mountain gorillas show that these costs may be sufficient to reduce female reproductive success as group size increases. Advantages to being with high quality males apparently can outweigh these costs. The implications of these data for the evolution of the mountain gorilla social system, and the possible roles of male protection, predation, and female/female competition in this regard, are discussed.