Behaviour In Wild Populations Research Articles

Hybridization in Canids-A Case Study of Pampas Fox (Lycalopex gymnocercus) and Domestic Dog (Canis lupus familiaris) Hybrid.

Hybridization between species with different evolutionary trajectories can be a powerful threat to wildlife conservation. Anthropogenic activities, such as agriculture and livestock, have led to the degradation and loss of natural habitats for wildlife. Consequently, the incidence of interspecific hybridization between wild and domestic species has increased, although cases involving species of different genera are rare. In Vacaria, a Southern city in Brazil, a female canid with a strange phenotype, which had characteristics between the phenotype of the domestic dog (Canis familiaris) and that of the pampas fox (Lycalopex gymnocercus), was found. Our analysis suggests that the animal is a hybrid between a domestic dog and a pampas fox, but future studies are necessary to investigate additional cases of this hybridization in nature. This finding worries for the conservation of wild canids in South America, especially concerning Lycalopex species. Hybridization with the domestic dog may have harmful effects on pampas fox populations due to the potential for introgression and disease transmission by the domestic dog. Therefore, future studies to explore the consequences of hybridization on genetics, ecology, and behavior of wild populations will be essential to improve the conservation of this species.

How can the MHC mediate social odor via the microbiota community? A deep dive into mechanisms

AbstractGenes of the major histocompatibility complex (MHC) have long been linked to odor signaling and recently researchers’ attention has focused on MHC structuring of microbial communities and how this may in turn impact odor. However, understanding of the mechanisms through which the MHC could affect the microbiota to produce a chemical signal that is both reliable and strong enough to ensure unambiguous transmission of behaviorally important information remains poor. This is largely because empirical studies are rare, predictions are unclear, and the underlying immunological mechanisms governing MHC–microbiota interactions are often neglected. Here, we review the immunological processes involving MHC class II (MHC-II) that could affect the commensal community. Focusing on immunological and medical research, we provide background knowledge for nonimmunologists by describing key players within the vertebrate immune system relating to MHC-II molecules (which present extracellular-derived peptides, and thus interact with extracellular commensal microbes). We then systematically review the literature investigating MHC–odor–microbiota interactions in animals and identify areas for future research. These insights will help to design studies that are able to explore the role of MHC-II and the microbiota in the behavior of wild populations in their natural environment and consequently propel this research area forward.

Hormone-mediated foraging strategies in an uncertain environment: Insights into the at-sea behavior of a marine predator.

Hormones are extensively known to be physiological mediators of energy mobilization and allow animals to adjust behavioral performance in response to their environment, especially within a foraging context.Few studies, however, have narrowed focus toward the consistency of hormonal patterns and their impact on individual foraging behavior. Describing these relationships can further our understanding of how individuals cope with heterogeneous environments and exploit different ecological niches.To address this, we measured between‐ and within‐individual variation of basal cortisol (CORT), thyroid hormone T3, and testosterone (TEST) levels in wild adult female Galápagos sea lions (Zalophus wollebaeki) and analyzed how these hormones may be associated with foraging strategies. In this marine predator, females exhibit one of three spatially and temporally distinct foraging patterns (i.e., “benthic,” “pelagic,” and “night” divers) within diverse habitat types.Night divers differentiated from other strategies by having lower T3 levels. Considering metabolic costs, night divers may represent an energetically conservative strategy with shorter dive durations, depths, and descent rates to exploit prey which migrate up the water column based on vertical diel patterns.Intriguingly, CORT and TEST levels were highest in benthic divers, a strategy characterized by congregating around limited, shallow seafloors to specialize on confined yet reliable prey. This pattern may reflect hormone‐mediated behavioral responses to specific risks in these habitats, such as high competition with conspecifics, prey predictability, or greater risks of predation.Overall, our study highlights the collective effects of hormonal and ecological variation on marine foraging. In doing so, we provide insights into how mechanistic constraints and environmental pressures may facilitate individual specialization in adaptive behavior in wild populations.

Increasing conservation translocation success by building social functionality in released populations

The importance of animal behavior to successful wildlife translocations has been acknowledged in recent decades, and it has been increasingly considered and more frequently incorporated into translocation management and research. However, explicit consideration of social behavior is often overlooked in this context. Social relationships take a variety of forms (e.g., cooperative partners, members of a dominance hierarchy, territorial neighbors) and play important roles in survival, reproduction, and resource exploitation. We review the ways in which concepts from studies of social behavior in wild populations may be leveraged to increase translocation success. Social structure and cohesion, social roles, social learning, and social competency may all be important to consider in building populations that are resilient and likely to persist. We argue that relevant data collected at all stages of translocation, including candidate selection, and during pre-release, release, and post-release monitoring, may inform the establishment of functional social structure post-release in species dependent on social processes. Integrating knowledge of social behavior into management decisions may be particularly useful when comparing the success of alternative release protocols or release candidate behavioral traits. Complementary datasets on a range of fitness-related metrics post-release will further leverage our understanding of social establishment in translocated populations. We illustrate the potential of these ideas using Asian and African elephants as a model. Both species are particularly challenging to manage but are translocated frequently; thus, evidence-based protocols for conservation translocations of elephants are urgently needed.

Lack of introgression of Japanese quail in a captive population of common quail

Farm-reared quails are released to the wild in Europe in vast numbers every year to increase hunting bag quotas. Experimental studies indicate that rather than the native common quail (Coturnix coturnix), the restocking is often done with domestic Japanese quail (Coturnix japonica) or with hybrids of domestic Japanese quail and common quail. Such practices are thought to be a severe threat for the native species as it could lead to introgression of domestic Japanese quail alleles into the wild common quail genome and potentially alter the migratory and reproductive behaviour in wild populations. In this study, we assessed the genetic purity of a captive population of common quail that was established from wild-caught founders caught on the Southern Italian coast in Sicily (Italy). We evaluated the proportion of ancestry to common and Japanese quail in this captive population via genetic screening using nuclear microsatellite markers and mitochondrial DNA analyses. We showed that the captive farm quail in our study had no sign of admixture with domestic Japanese quail and had similar genotype frequencies relative to wild common quail, confirming the success of the breeding programme for the native species. We propose that raising common quails in captivity for restocking purposes rather than domestic Japanese quails or hybrids would be a feasible alternative that could minimise the risk of genetic pollution of wild common quail populations.

Individual variation in reproductive behaviour is linked to temporal heterogeneity in predation risk.

Variation in predation risk is a major driver of ecological and evolutionary change, and, in turn, of geographical variation in behaviour. While predation risk is rarely constant in natural populations, the extent to which variation in predation risk shapes individual behaviour in wild populations remains unclear. Here, we investigated individual differences in reproductive behaviour in 16 Trinidadian guppy populations and related it to the observed variation in predator biomass each population experienced. Our results show that high heterogeneity in predator biomass is linked to individual behavioural diversification. Increased within-population heterogeneity in predator biomass is also associated with behavioural polymorphism. Some individuals adjust the frequency of consensual mating behaviour in response to differences in sex ratio context, while others display constantly at elevated frequencies. This pattern is analogous to a 'live fast, die young' pace-of-life syndrome. Notably, both high and low mean differences in predator biomass led to a homogenization of individual frequency of consensual mating displays. Overall, our results demonstrate that individual behavioural variation is associated with heterogeneity in predator biomass, but not necessarily with changes in mean values of predator biomass. We suggest that heterogeneity in predator biomass is an informative predictor of adaptive responses to changes in biotic conditions.

Diffusion of novel foraging behaviour in Amazon parrots through social learning.

While social learning has been demonstrated in species across many taxa, the role it plays in everyday foraging decisions is not well understood. Investigating social learning during foraging could shed light on the emergence of cultural variation in different groups. We used an open diffusion experiment to examine the spread of a novel foraging technique in captive Amazon parrots. Three groups were tested using a two-action foraging box, including experimental groups exposed to demonstrators using different techniques and control birds. We also examined the influence of agonistic and pilfering behaviour on task acquisition. We found evidence of social learning: more experimental birds than control birds interacted with and opened the box. The birds were, however, no more likely to use the demonstrated technique than the non-demonstrated one, making local or stimulus enhancement the most likely mechanism. Exhibiting aggression was positively correlated with box opening, whilst receiving aggression did not reduce motivation to engage with the box, indicating that willingness to defend access to the box was important in task acquisition. Pilfering food and success in opening the box were also positively correlated; however, having food pilfered did not affect victims' motivation to interact with the box. In a group context, pilfering may promote learning of new foraging opportunities. Although previous studies have demonstrated that psittacines are capable of imitation, in this naturalistic set-up there was no evidence that parrots copied the demonstrated opening technique. Foraging behaviour in wild populations of Amazons could therefore be facilitated by low-fidelity social learning mechanisms.

Nonlethal predator effects on the turn-over of wild bird flocks.

Nonlethal predator effects arise when individuals of a prey species adjust their behaviour due to the presence of predators. Non-lethal predator effects have been shown to affect social group structure and social behaviour as well as individual fitness of the prey. In this experimental study, we used model sparrowhawks to launch attacks on flocks of wild great tits and blue tits whilst monitoring their social dynamics. We show that nonlethal attacks caused instantaneous turn-over and mixing of group composition within foraging flocks. A single experimental ‘attack’ lasting on average less than three seconds, caused the amount of turn-over expected over three hours (2.0–3.8 hours) of undisturbed foraging. This suggests that nonlethal predator effects can greatly alter group composition within populations, with potential implications for social behaviour by increasing the number of potential interaction partners, as well as longer-term consequences for pair formation and emergent effects determined by social structure such as information and disease transmission. We provide the first evidence, to our knowledge, based on in depth monitoring of a social network to comprehensively support the hypothesis that predators influence the social structure of groups, which offers new perspectives on the key drivers of social behaviour in wild populations.

Antennation and sexual performance of male digger wasps Sphex ingens Smith (Hymenoptera: Sphecidae)

ABSTRACTAntennation can play several roles in hymenopteran copulation, mainly in wasps. The digger wasp Sphex ingens Smith has a very peculiar sexual behaviour, in which forced copulation is a striking element. However, communication through antennation during the pre-copulation and copulation phases and the relationship between the sexual performance of males and the final result of copulation require further clarification. The sexual behaviour of wild populations of S. ingens was filmed during the breeding season in a site between the beaches Meros and Aventureiro, Ilha Grande, southeastern Brazil. We assessed antennation behaviour, courtship duration, sexual performance, and genital clasping. Only successful males had the genital clasping assessed. Evidence found so far points out that the successful males showed better sexual performance – that is, they antennated more in a shorter courtship duration. Also, genital clasping in successful males did not depend on antennation, courtship duration, or sexual performance. Our results shed light on some aspects of the sexual behaviour of wasps, as they explain part of the sexual selection mechanisms adopted by the species.

Effects of Ectoparasitism on Behavioral Thermoregulation in the Tropical lizards Anolis cybotes (Squamata: Dactyloidae) and Anolis armouri (Squamata: Dactyloidae)

A febrile response, or a raised body temperature in response to infection, has been widely documented in various species of reptiles in laboratory trials. However, whether and how behavioral fever is achieved in nature remains almost entirely unknown. Here, we examine whether two species of lizard in the cybotoid clade of Hispaniolan trunk-ground anoles (Anolis cybotes and Anolis armouri) change their basking behavior in response to infestation by the chigger mite, Eutrombicula alfreddugesi. We examined body temperature and basking behavior in wild populations of A. cybotes and A. armouri from four localities that spanned a 2,000-m elevational transect in the Sierra de Baoruco, Dominican Republic. Although basking rate increased with elevation, we found that it did not correlate with mite load. Body temperature was also unrelated to parasite load. Thus, we found that E. alfreddugesi infestation did not induce behavioral fever in these anoles. We found a strong altitudinal pattern in chigger infestations: Infestations levels were highest in lizards from mid-elevation and dropped dramatically at low and high elevation (particularly in the latter). We discuss possible mechanisms for this altitudinal pattern in chigger infestation and discuss the relationship between infection and behavioral thermoregulation in lizards.

Divorce and Infidelity Are Associated with Skewed Adult Sex Ratios in Birds

Adult sex ratio (ASR) is a fundamental concept in population demography, and recent theory suggests that ASR plays a central role in social behavior, mating systems, and parental care. Unbalanced ASRs are predicted to influence pair-bond and mating behavior, since the rarer sex in the population has more potential partners to mate with than the more common sex. Here we use phylogenetic comparative analyses to test whether ASR is related to three major aspects of mating behavior: divorce, social polygamy, and pair-bond infidelity. ASR is strongly correlated with long-term pair bonds, since the divorce rate is higher in species with a female-biased sex ratio, indicating that mate change by pair members and/or breaking of pair bonds by unmated individuals is more frequent when females outnumber males. Short-term pair bonds are also associated with unbalanced ASRs: males are more commonly polygamous when females outnumber males, and conversely, females are more polygamous when males outnumber females. Furthermore, infidelity increases with male-biased ASR in socially monogamous birds, suggesting that male coercion and/or female willingness to cheat the partner are facilitated by male-biased ASR. Our results provide the first comprehensive support for the proposition that ASR influences multiple aspects of pair-bond and mating behavior in wild populations.

Effects of group size, habitat and hunting risk on vigilance and foraging behaviour in the Lesser Rhea (Rhea pennata pennata)

Gregariousness is a known anti-predator strategy, but factors other than the size of groups, such as the levels of predation pressure or habitat, can affect vigilance and foraging behaviour in birds. We studied the effects of group size, habitat (shrubland steppe v. meadows), and risk of hunting by humans (protected core area v. edge area exposed to poaching) on vigilance and foraging behaviour of wild populations of the Lesser Rhea (Rhea pennata pennata), a near-threatened ratite, in north-western Patagonia, Argentina. On average, Lesser Rheas allocated 18% of their time to vigilance and 67% to foraging. Individuals tended to be more vigilant with declining group size, in areas with low visibility that hinders escape by running, and in areas exposed to hunting, than in open habitats with abundant food or sites with low risk of hunting. Although time spent foraging was also influenced by habitat type and hunting risk, there was no direct relationship between foraging time and group size. As in other species of ratite, Lesser Rheas seem to take advantage of flocking as an anti-predation strategy. Our data do not only confirm the influence of group size, but also of habitat structure and hunting risk, in determining the behaviour of this flightless bird in the wild.

Tonic immobility is a measure of boldness toward predators: an application of Bayesian structural equation modeling

Animals attacked by predators often enter a state of tonic immobility (TI) in which individuals appear to simulate death. Despite the fact that TI is often used as a proxy of fear in domesticated animals, quantitative data on individual variation is very scarce for wild vertebrates. As a consequence, we lack ecological interpretations for the variability in TI that may exist in wild populations. Here, we tested whether there are consistent differences among individuals in 2 components of TI within wild populations of 2 avian species, the Yellow-crowned bishop (Euplectes afer) and the Tree sparrow (Passer montanus). We next tested whether this variation reflects variation in boldness toward predators (measured as the response to 2 predator models) or is simply related to variation in general activity/restlessness (measured as baseline activity) in the bishop. We analyzed our data by means of Bayesian structural equation modeling (SEM), which has several general advantages and, moreover, allowed us to analyze censored (truncated) data. We found good support for relatively high repeatability within individuals of both components of TI. Measures of TI appeared to be uncorrelated with baseline activity. In contrast, our results suggest that individual variation in TI in a wild vertebrate can be interpreted in a context of boldness toward predators, making TI a meaningful and practical behavioral trait for studies involving personality and antipredation behavior in wild populations. In addition, we show that the Bayesian structural equation modeling approach to analyze censored data had greater statistical power than other approaches. Hence, this rarely implemented technique deserves to be more widely used. Key words: activity, animal personality, antipredation behavior, Bayesian structural equation modeling, boldness, fear, repeatability, tonic immobility. [Behav Ecol]

Controlling disease outbreaks in wildlife using limited culling: modelling classical swine fever incursions in wild pigs in Australia.

Disease modelling is one approach for providing new insights into wildlife disease epidemiology. This paper describes a spatio-temporal, stochastic, susceptible- exposed-infected-recovered process model that simulates the potential spread of classical swine fever through a documented, large and free living wild pig population following a simulated incursion. The study area (300 000 km2) was in northern Australia. Published data on wild pig ecology from Australia, and international Classical Swine Fever data was used to parameterise the model. Sensitivity analyses revealed that herd density (best estimate 1-3 pigs km-2), daily herd movement distances (best estimate approximately 1 km), probability of infection transmission between herds (best estimate 0.75) and disease related herd mortality (best estimate 42%) were highly influential on epidemic size but that extraordinary movements of pigs and the yearly home range size of a pig herd were not. CSF generally established (98% of simulations) following a single point introduction. CSF spread at approximately 9 km2 per day with low incidence rates (< 2 herds per day) in an epidemic wave along contiguous habitat for several years, before dying out (when the epidemic arrived at the end of a contiguous sub-population or at a low density wild pig area). The low incidence rate indicates that surveillance for wildlife disease epidemics caused by short lived infections will be most efficient when surveillance is based on detection and investigation of clinical events, although this may not always be practical. Epidemics could be contained and eradicated with culling (aerial shooting) or vaccination when these were adequately implemented. It was apparent that the spatial structure, ecology and behaviour of wild populations must be accounted for during disease management in wildlife. An important finding was that it may only be necessary to cull or vaccinate relatively small proportions of a population to successfully contain and eradicate some wildlife disease epidemics.

Adaptive responses and disruptive effects: how major wildfire influences kinship‐based social interactions in a forest marsupial

Environmental disturbance is predicted to play a key role in the evolution of animal social behaviour. This is because disturbance affects key factors underlying social systems, such as demography, resource availability and genetic structure. However, because natural disturbances are unpredictable there is little information on their effects on social behaviour in wild populations. Here, we investigated how a major wildfire affected cooperation (sharing of hollow trees) by a hollow-dependent marsupial. We based two alternative social predictions on the impacts of fire on population density, genetic structure and resources. We predicted an adaptive social response from previous work showing that kin selection in den-sharing develops as competition for den resources increases. Thus, kin selection should occur in burnt areas because the fire caused loss of the majority of hollow-bearing trees, but no detectable mortality. Alternatively, fire may have a disruptive social effect, whereby postfire home range-shifts 'neutralize' fine-scale genetic structure, thereby removing opportunities for kin selection between neighbours. Both predictions occurred: the disruptive social effect in burnt habitat and the adaptive social response in adjacent unburnt habitat. The latter followed a massive demographic influx to unburnt 'refuge' habitat that increased competition for dens, leading to a density-related kin selection response. Our results show remarkable short-term plasticity of animal social behaviour and demonstrate how the social effects of disturbance extend into undisturbed habitat owing to landscape-scale demographic shifts. We predicted long-term changes in kinship-based cooperative behaviour resulting from the genetic and resource impacts of forecast changes to fire regimes in these forests.

Pollution diminishes intra-specific aggressiveness between wood ant colonies

A variety of common environmental pollutants are known to affect the animal behaviour, but the occurrence and extent of pollution-induced behavioural changes in wild populations are practically unknown. Here we show that heavy metal pollution reduces the normal intra-specific aggressive behaviour in wild populations of the wood ant, Formica aquilonia, a dominant territorial ant species in boreal forests. Ants exposed to long-term pollution around a copper smelter showed higher heavy metal concentrations and were less aggressive towards the member of foreign unpolluted colony than the ants from an uncontaminated area. A pollution-related decline in the level of aggressiveness in this keystone general predator species may potentially affect the structure of invertebrate community of boreal and temperate forests. Further studies are needed to find out whether the change in aggressiveness is directly caused by metal toxicity or indirectly via secondary pollution effects, such as changed resource levels.

The nature of Drosophila melanogaster

Our understanding of the cellular mechanisms underlying behaviour has been vastly improved by the growing number of functional genetic techniques, candidate genes for behaviour, and descriptions of the neurogenetic aspects of behaviour in D. melanogaster. By integrating these data with studies on ecological patterns of natural behaviour variation (and its relationship to environmental heterogeneity) we can begin to make important links between ecology and behaviour that may be applied across varied taxa [22xCandidate genes for behavioural ecology. Fitzpatrick, M.J., Ben-Shahar, Y., Smid, H.M., Vet, L.E.M., Robinson, G.E., and Sokolowski, M.B. Trends Ecol. Evol. 2005; 20: 96–104Abstract | Full Text | Full Text PDF | PubMed | Scopus (144)See all References][22]. We expect such integration to not only lead to the identification of new behaviours, such as those involving social interactions, but also to an understanding of how these behaviours are affected by temporal and spatial heterogeneity in the natural environment (Figure 1Figure 1). Rewards abound for such pursuits with promises of gaining new insights into the evolution of complex behaviours and their underlying genetic architecture. Studying behaviour in wild populations may help us to identify genes and traits that are important for local adaptation and speciation. Key to such pursuits is assaying naturally derived populations with precisely described ecologies under highly controlled yet realistic lab conditions.Figure 1Examples of Drosophila melanogaster in a natural setting.In nature, individuals might interact on fruit, leaves, branches, or grass. For example, at top right, a male courts female on a blade of grass. Or, at bottom right, two males posture prior to an aggressive interaction. (Photographs by Christopher J. Reaume.)View Large Image | View Hi-Res Image | Download PowerPoint SlideThe prospects for attaining a complete understanding of the biology of an organism have never been as exciting as they are today. The little fruit fly, a nuisance in many of our kitchens, has facilitated the acquisition of knowledge on genetics, development, neurobiology, and behaviour — all of which were thought unimaginable before the turn of the 19th century. Where some might see an opportunistic human commensal, others will see a symbiont where food and habitat is traded for biological insights of remarkable breadth.

Using the triple test cross to investigate the genetics of behavior in wild populations. I. Methodological considerations.

The rationale for using the triple test cross breeding design to investigate the genetics of behavior in wild populations is outlined. The breeding design, biometrical models, and methods of analysis are specified and the limitations on the interpretation of studies are discussed, especially in relation to the need for adequate tester lines.