Parasitism and the evolutionary ecology of animal personality

The ecological factors responsible for the evolution of individual differences in animal personality (consistent individual differences in the same behaviour across time and contexts) are currently the subject of intense debate. A limited number of ecological factors have been investigated to date, with most attention focusing on the roles of resource competition and predation. We suggest here that parasitism may play a potentially important, but largely overlooked, role in the evolution of animal personalities. We identify two major routes by which parasites might influence the evolution of animal personality. First, because the risk of acquiring parasites can be influenced by an individual's behavioural type, local parasite regimes may impose selection on personality traits and behavioural syndromes (correlations between personality traits). Second, because parasite infections have consequences for aspects of host 'state', parasites might induce the evolution of individual differences in certain types of host behaviour in populations with endemic infections. Also, because infection often leads to specific changes in axes of personality, parasite infections have the potential to decouple behavioural syndromes. Host-parasite systems therefore provide researchers with valuable tools to study personality variation and behavioural syndromes from a proximate and ultimate perspective.     

Environmental drivers of demographics, habitat use, and behavior during a post-Pleistocene radiation of Bahamas mosquitofish (Gambusia hubbsi)

A fundamental goal of evolutionary ecology is to understand the environmental drivers of ecological divergence during the early stages of adaptive diversification. Using the model system of the post-Pleistocene radiation of Bahamas mosquitofish (Gambusia hubbsi) inhabiting blue holes, we used a comparative field study to examine variation in density, age structure, tertiary (adult) sex ratio, habitat use, as well as adult feeding and social behaviors in relation to environmental features including predation risk, interspecific competition, productivity (e.g. chlorophyll a, zooplankton density), and abiotic factors (e.g. salinity, surface diameter). The primary environmental factor associated with ecological differentiation in G. hubbsi was the presence of piscivorous fish. Gambusia hubbsi populations coexisting with predatory fish were less dense, comprised of a smaller proportion of juveniles, and were more concentrated in shallow, near-shore regions of blue holes. In addition to predation risk, the presence of a competitor fish species was associated with G. hubbsi habitat use, and productivity covaried with both age structure and habitat use. Feeding and social behaviors differed considerably between sexes, and both sexes showed behavioral differences between predator regimes by exhibiting more foraging behaviors in the absence of predators and more sexual behaviors in their presence. Males additionally exhibited more aggressive behaviors toward females in the absence of predators, but were more aggressive toward other males in the presence of predators. These results largely matched a priori predictions, and several findings are similar to trends in other related systems. Variation in predation risk appears to represent the primary driver of ecological differentiation in this system, but other previously underappreciated factors (interspecific competition, resource availability) are notable contributors as well. This study highlights the utility of simultaneously evaluating multiple environmental factors and multiple population characteristics within a natural system to pinpoint environmental drivers of ecological differentiation.     

How the cascading effects of a single behavioral trait can generate personality

Individuals from the same population generally vary in suites of correlated behavioral traits: personality. Yet, the strength of the behavioral correlations sometimes differs among populations and environmental conditions, suggesting that single underlying mechanisms, such as genetic constraints, cannot account for them. We propose, instead, that such suites of correlated traits may arise when a single key behavior has multiple cascading effects on several other behaviors through affecting the range of options available. For instance, an individual's shyness can constrain its habitat choice, which, in turn, could restrict the expression of other behavioral traits. We hypothesize that shy individuals should be especially restrained in their choice of habitat when the risk of predation is high, which then canalizes them into different behavioral options making them appear behaviorally distinct from bolder individuals. We test this idea using an individual‐based simulation model. Our results show that individual differences in boldness can be sufficient, under high predation pressure, to generate behavioral correlations between boldness and both the tendency to aggregate and the propensity to use social information. Thus, our findings support the idea that some behavioral syndromes can be, at least to some extent, labile. Our model further predicts that such cascading effects should be more pronounced in populations with a long history of predation, which are expected to exhibit a low average boldness level, compared with predator‐naïve populations.     

The ontogeny of personality traits in the desert funnel‐web spider,Agelenopsis lisa (Araneae: Agelenidae)

Trait consistency over time is one of the cornerstones of animal personality. Behavioral syndromes are the result of correlations between behaviors. While repeatability in behavior is not a requirement for behavioral syndromes, the two concepts studied together provide a more comprehensive understanding of how behavior can change over ontogeny. The roles of ontogenetic processes in the emergence of personality and behavioral syndromes have received much individual attention. However, the characterization of both individual trait consistency and behavioral syndromes across both sexes, as in our study, has been relatively rare. Ontogeny refers to changes that occur from conception to maturation, and juveniles might be expected to undergo different selection pressures than sexually mature individuals and also will experience profound changes in hormones, morphology, and environment during this period. In this study, we test for behavioral trait consistency and behavioral syndromes across six time points during ontogenetic development in the desert funnel‐web spider (Agelenopsis lisa). Our results indicate behavioral traits generally lack consistency (repeatability) within life stages and across ontogeny. However, penultimate males and mature females do exhibit noticeable mean‐level changes, with greater aggressive responses toward prey, shorter latencies to explore their environment and in the exhibition of risk‐averse responses to predatory cues. These traits also show high repeatability. Some trait correlations do exist as well. In particular, a strong correlation between aggressiveness toward prey and exploration factors is observed in mature males. However, because correlations among these factors are unstable across ontogeny and vary in strength over time, we conclude that behavioral syndromes do not exist in this species. Nevertheless, our results indicate that increased consistency, increasing average trait values, and varying correlations between traits may coincide with developmentally important changes associated with sexual maturation, albeit at different time points in males and females. This period of the life cycle merits systematic examination across taxa.     

Quantifying habitat-dependent mortality risk in lacustrine fishes by means of tethering trials and survival analyses

Habitat features influence the ecological interactions and spatial distribution of fish species. For example, water transparency and macrophyte cover, as well as their interaction, can strongly influence predation risk and mortality. Tethering trials were conducted in Lake St. Pierre (Quebec, Canada) to assess the effects of water transparency and macrophyte cover on the mortality risk of eight abundant fish species; Brown Bullhead (Ameiurus nebulosus), Mooneye (Hiodon tergisus), Emerald Shiner (Notropis atherinoides), Golden Shiner (Notropis crysoleucas), Blacknose Shiner (Notropis heterolepis), Spottail Shiner (Notropis hudsonius), Trout-perch (Percopsis omiscomaycus), and Yellow Perch (Perca flavescens). Kaplan–Meier survival curves showed that mortality risk varied substantially among three groups of species having high, intermediate, or low survival rates. Species with spines appeared to have higher survival rates, consistent with the notion that spines deter predators. Cox regression models showed that mortality risk for six of the eight species was influenced by water transparency or an interaction of transparency with macrophyte cover. Mortality risk was generally greatest at low transparency. Variation in water transparency may generate spatial heterogeneity in fish abundance, either through direct effects, such as local reduction in prey numbers by predation, or indirect effects, such as behavioural avoidance of risky areas by prey.     

高体鳑鲏化学预警响应与“个性”行为的关联

化学通讯是水生动物最原始、最普遍和最主要的通讯方式之一。对捕食风险源的回避可以使猎物减少被捕食风险,但如果出现的化学信息并不代表真正的威胁,那么就会导致猎物减少觅食或求偶的机会,从而降低适合度。因此基于能量代价-生态收益的权衡可能导致动物行为决策与化学通讯模式的分化。"个性"行为（Personality）已被证实与动物的行为决定有关,然而,有关鱼类化学预警通讯与"个性"行为关联的研究至今鲜见报道。推测："个性"行为是鱼类的化学通讯模式多样化的重要内因。采捕了广泛分布于我国淡水水域的野生高体鳑鲏（Rhodeus ocellatus）并于半自然状态下探究了：（1）实验鱼对不同化学信息（池水对照组、柠檬新奇信息组、高浓度和低浓度化学预警信息（Chemical alarm cues,CAC）组）的行为响应,（2）实验鱼在新异环境（被转入新栖息地）、新异刺激（新异物理刺激）、新异食物资源下的"个性"行为及其与化学预警响应的关联。结果发现：（1）不同溶液化学信息对实验鱼静止时间与爆发游泳的变化以及摄食个体的比例等参数均有显著影响（P < 0.05）。其中,柠檬组（未知"假风险"）与对照组相比无显著差异（P > 0.05）,实验鱼对不同浓度CAC（已知"真风险"）表现出不同程度的行为响应,高浓度和低浓度CAC均导致摄食个体比例下降（P < 0.05）,但只有高浓度CAC导致静止时间和爆发游泳的变化增加（P < 0.05）。可见,实验鱼对外源化学信息有准确高效的行为应答。（2）实验鱼静止时间比对不同溶液化学预警响应的变化与新异刺激下的活跃性显著负相关（P < 0.05）,但与新异环境下的活跃性无关（P > 0.05）,提示"个性"行为与化学预警响应有关但这种关联可能又有一定的环境依赖性（例如测试环境的稳定性与可预测性）。     

Stability of behavioral syndromes but plasticity in individual behavior: consequences for rockfish stock enhancement

This study investigated behavioral syndromes, which are defined as correlations between behaviors. Behavioral syndromes can lead to the unintentional alteration of a wide range of behavioral traits of hatchery fish if unintentional selection on one behavior leads to selection on a correlated behavior. Specifically, this study used brown rockfish, Sebastes auriculatus, to test the hypothesis that a fish that feeds at high rates in the absence of a predator also takes more risks when a predator is present, and that through such a correlation, unintentional hatchery selection for high feeding rates may also lead to changes in risk taking behavior (here defined as behavior that increases predation risk). Behavioral syndromes were found—feeding behavior in the absence of a predator tended to correlate positively with both feeding behavior in the presence of a predator model and time near the model. These syndromes were stable through time—that is, the same correlations appeared 10 days later when the behavioral assays were repeated. However individual behavior was inconsistent (plastic). A fish could both feed and take risks at high rates on Day 1, but then both feed and take risks at low rates on Day 10. Thus, while behavioral syndromes were stable (i.e. present in both rounds 1 and 2), individuals were plastic in their behavior (i.e. inconsistent between rounds 1 and 2). After 16 weeks of hatchery rearing, neither growth nor survival were predicted by behavior. It is suggested that the behavioral plasticity within individuals through time makes consistent selection for strong feeders less likely, and that species with more plastic behavior may be less susceptible to unintentional selection on behavioral syndromes than species with behavior that is more fixed.     

Personality traits and behavioral syndromes in differently urbanized populations of house sparrows (Passer domesticus)

Urbanization creates novel environments for wild animals where selection pressures may differ drastically from those in natural habitats. Adaptation to urban life involves changes in various traits, including behavior. Behavioral traits often vary consistently among individuals, and these so-called personality traits can be correlated with each other, forming behavioral syndromes. Despite their adaptive significance and potential to act as constraints, little is known about the role of animal personality and behavioral syndromes in animals' adaptation to urban habitats. In this study we tested whether differently urbanized habitats select for different personalities and behavioral syndromes by altering the population mean, inter-individual variability, and correlations of personality traits. We captured house sparrows (Passer domesticus) from four different populations along the gradient of urbanization and assessed their behavior in standardized test situations. We found individual consistency in neophobia, risk taking, and activity, constituting three personality axes. On the one hand, urbanization did not consistently affect the mean and variance of these traits, although there were significant differences between some of the populations in food neophobia and risk taking (both in means and variances). On the other hand, both urban and rural birds exhibited a behavioral syndrome including object neophobia, risk taking and activity, whereas food neophobia was part of the syndrome only in rural birds. These results indicate that there are population differences in certain aspects of personality in house sparrows, some of which may be related to habitat urbanization. Our findings suggest that urbanization and/or other population-level habitat differences may not only influence the expression of personality traits but also alter their inter-individual variability and the relationships among them, changing the structure of behavioral syndromes.     

Within‐Individual Correlations Reveal Link Between a Behavioral Syndrome,Condition, and Cortisol in Free‐Ranging Belding's Ground Squirrels

Animals often exhibit consistent individual differences in behavior (i.e., animal personality) and correlations between behaviors (i.e., behavioral syndromes), yet the causes of those patterns of behavioral variation remain insufficiently understood. Many authors hypothesize that state‐dependent behavior produces animal personality and behavioral syndromes. However, empirical studies assessing patterns of covariation among behavioral traits and state variables have produced mixed results. New statistical methods that partition correlations into between‐individual and residual within‐individual correlations offer an opportunity to more sufficiently quantify relationships among behaviors and state variables to assess hypotheses of animal personality and behavioral syndromes. In a population of wild Belding's ground squirrels (Urocitellus beldingi), we repeatedly measured activity, exploration, and response to restraint behaviors alongside glucocorticoids and nutritional condition. We used multivariate mixed models to determine whether between‐individual or within‐individual correlations drive phenotypic relationships among traits. Squirrels had consistent individual differences for all five traits. At the between‐individual level, activity and exploration were positively correlated whereas both traits negatively correlated with response to restraint, demonstrating a behavioral syndrome. At the within‐individual level, condition negatively correlated with cortisol, activity, and exploration. Importantly, this indicates that although behavior is state‐dependent, which may play a role in animal personality and behavioral syndromes, feedback mechanisms between condition and behavior appear not to produce consistent individual differences in behavior and correlations between them.     

Ecological consequences of the bold–shy continuum: the effect of predator boldness on prey risk

Although the existence of different personality traits within and between animal populations has been relatively well established, the ecological implications of this variation remain neglected. In this study we tested whether differences in the boldness of pairs of three-spined sticklebacks led to differential predation risk in their prey, Chironomidae larvae. Bolder pairs, those that left a refuge and crossed the tank mid-line sooner, ate a greater proportion of prey in 10 min than less bold fish (therefore prey were at a greater per capita risk). Fish crossed the mid-line more rapidly when a larger number of prey were presented, suggesting they accepted greater risk in return for a larger foraging reward. Perception of predation risk also affected the differences between fish in boldness, as larger fish crossed the mid-line sooner after leaving the refuge (larger fish are less at risk from predation). Hence, an interesting trophic interaction occurs, where the risk experienced by the chironomid larvae is determined by the risk perceived by their predators. Through the variation generated by boldness, a form of behaviourally mediated trophic cascade can occur within (as well as between) communities.     

Combined Effects of Turbulence and Different Predation Regimes on Zooplankton in Highly Colored Water—Implications for Environmental Change in Lakes

In aquatic ecosystems, predation is affected both by turbulence and visibility, but the combined effects are poorly known. Both factors are changing in lakes in the Northern Hemisphere; the average levels of turbulence are predicted to increase due to increasing wind activities, while water transparency is decreasing, e.g., due to variations in precipitation, and sediment resuspension. We explored experimentally how turbulence influenced the effects of planktivorous fish and invertebrate predators on zooplankton when it was combined with low visibility caused by high levels of water color. The study was conducted as a factorial design in 24 outdoor ponds, using the natural zooplankton community as a prey population. Perch and roach were used as vertebrate predators and Chaoborus flavicans larvae as invertebrate predators. In addition to calm conditions, the turbulent dissipation rate used in the experiments was 10⁻⁶ m² s⁻³, and the water color was 140 mg Pt L⁻¹. The results demonstrated that in a system dominated by invertebrates, predation pressure on cladocerans increased considerably under intermediate turbulence. Under calm conditions, chaoborids caused only a minor reduction in the crustacean biomass. The effect of fish predation on cladocerans was slightly reduced by turbulence, while predation on cyclopoids was strongly enhanced. Surprisingly, under turbulent conditions fish reduced cyclopoid biomass, whereas in calm water it increased in the presence of fish. We thus concluded that turbulence affects fish selectivity. The results suggested that in dystrophic invertebrate-dominated lakes, turbulence may severely affect the abundance of cladocerans. In fish-dominated dystrophic lakes, on the other hand, turbulence-induced changes in planktivory may considerably affect copepods instead of cladocerans. In lakes inhabited by both invertebrates and fish, the response of top-down regulation to turbulence resembles that in fish-dominated systems, due to intraguild predation. The changes in planktivorous predation induced by abiotic factors may possibly cascade to primary producers.     

Predation‐associated divergence of male genital morphology in a livebearing fish

Male genital morphology is remarkably diverse across internally fertilizing animals, a phenomenon largely attributed to sexual selection. Ecological differences across environments can alter the context of sexual selection, yet little research has addressed how this may influence the rapid, divergent evolution of male genitalia. Using the model system of Bahamas mosquitofish (Gambusia hubbsi) undergoing ecological speciation across blue holes, we used geometric morphometric methods to test (i) whether male genital shape (the small, approximately 1 mm long, distal tip of the sperm‐transfer organ, the gonopodium) has diverged between populations with and without predatory fish and (ii) whether any observed divergence has a genetic basis. We additionally examined the effects of genetic relatedness and employed model selection to investigate other environmental factors (i.e. interspecific competition, adult sex ratio and resource availability) that could potentially influence genital shape via changes in sexual selection. Predation regime comprised the most important factor associated with male genital divergence in this system, although sex ratio and some aspects of resource availability had suggestive effects. We found consistent, heritable differences in male genital morphology between predation regimes: Bahamas mosquitofish coexisting with predatory fish possessed more elongate genital tips with reduced soft tissue compared with counterparts inhabiting blue holes without predatory fish. We suggest this may reflect selection for greater efficiency of sperm transfer and fertilization during rapid and often forced copulations in high‐predation populations or differences in sexual conflict between predation regimes. Our study highlights the potential importance of ecological variation, particularly predation risk, in indirectly generating genital diversity.     

Refuge availability and sequence of predators determine the seasonal succession of crustacean zooplankton in a clay-turbid lake

The contribution of predators and abiotic factors to the regulation of the biomass and seasonal succession of crustacean zooplankton was studied in Lake Rehtijärvi (southern Finland). Field data in combination with bioenergetics modeling indicated that invertebrate planktivory by Chaoborus depressed cladoceran populations during early summer. In particular, bosminids that generally form the spring biomass peak of cladocerans in stratified temperate lakes did not appear in the samples until July. In July, predation pressure by chaoborids was relaxed due to their emergence period and cladoceran population growth appeared to be limited by predation by planktivorous fish. The effect of fish predation was amplified by reduced refuge availability for cladocerans. The concentration of dissolved oxygen below the epilimnion was depleted, forcing cladocerans to move upward to less turbid and thus more dangerous water layers. The effect of size selective predation by fish resulted in reduced mean size of cladocerans during the period when refuge thickness (thickness of the water layer with oxygen concentration <1 mg l^?1 and water turbidity >30 NTU) was lowest. The results confirmed that in clay-turbid lakes, invertebrate predators could be the main regulators of herbivorous zooplankton even when cyprinid fish are abundant.     

Risk, resources and state-dependent adaptive behavioural syndromes

Many animals exhibit behavioural syndromes-consistent individual differences in behaviour across two or more contexts or situations. Here, we present adaptive, state-dependent mathematical models for analysing issues about behavioural syndromes. We find that asset protection (where individuals with more 'assets' tend be more cautious) and starvation avoidance, two state-dependent mechanisms, can explain short-term behavioural consistency, but not long-term stable behavioural types (BTs). These negative-feedback mechanisms tend to produce convergence in state and behaviour over time. In contrast, a positive-feedback mechanism, state-dependent safety (where individuals with higher energy reserves, size, condition or vigour are better at coping with predators), can explain stable differences in personality over the long term. The relative importance of negative- and positive-feedback mechanisms in governing behavioural consistency depends on environmental conditions (predation risk and resource availability). Behavioural syndromes emerge more readily in conditions of intermediate ecological favourability (e.g. medium risk and medium resources, or high risk and resources, or low risk and resources). Under these conditions, individuals with higher initial state maintain a tendency to be bolder than individuals that start with low initial state; i.e. later BT is determined by state during an early 'developmental window'. In contrast, when conditions are highly favourable (low risk, high resources) or highly unfavourable (high risk, low resources), individuals converge to be all relatively bold or all relatively cautious, respectively. In those circumstances, initial differences in BT are not maintained over the long term, and there is no early developmental window where initial state governs later BT. The exact range of ecological conditions favouring behavioural syndromes depends also on the strength of state-dependent safety.     

Survival benefits and divergence of predator-induced behavior between pumpkinseed sunfish ecomorphs

Resource use is widely thought to influence adaptive phenotypicdivergence, whereas other ecological factors, such as predation,are frequently overlooked, particularly in studies of polyphenismin fishes. Juvenile pumpkinseed sunfish (Lepomis gibbosus) rearedwith predatory walleye (Sander vitreus) increase body depthand dorsal spine length, indicating that developmental responsesto predation can shape phenotype. Body form responses to thesame predator cues though have also evolutionarily divergedbetween sunfish ecomorphs that coexist in single lake populationsby inhabiting either littoral or pelagic habitats, suggestingthat predation risk varies between habitats. Here, we test ifprior exposure to predator cues influences the development ofbehavior in juvenile pumpkinseed sunfish, if behavioral responsesto the same predator cues vary between ecomorphs, and if inducedphenotypic variation affects survival under predation. Behaviordepended strongly on prior exposure to predator cues, but thiseffect varied between sunfish ecomorphs, indicating that ecomorphshave different responses to the same predator cues. Predator-inducedphenotypes had higher survival than control phenotypes undersimulated littoral but not pelagic conditions. Predator-inducedphenotypic responses are candidate-inducible defenses, and divergentresponses between ecomorphs suggest that they can evolve inresponse to selection imposed by differences in habitat-specificpredation risk.     

No personality without experience? A test on Rana dalmatina tadpoles

While the number of studies reporting the presence of individual behavioral consistency (animal personality, behavioral syndrome) has boomed in the recent years, there is still much controversy about the proximate and ultimate mechanisms resulting in the phenomenon. For instance, direct environmental effects during ontogeny (phenotypic plasticity) as the proximate mechanism behind the emergence of consistent individual differences in behavior are usually overlooked compared to environmental effects operating across generations (genetic adaptation). Here, we tested the effects of sociality and perceived predation risk during ontogeny on the strength of behavioral consistency in agile frog (Rana dalmatina) tadpoles in a factorial common garden experiment. Tadpoles reared alone and without predatory cues showed zero repeatability within (i.e., lack of personality) and zero correlation between (i.e., lack of syndrome) activity and risk‐taking. On the other hand, cues from predators alone induced both activity and risk‐taking personalities, while cues from predators and conspecifics together resulted in an activity – risk‐taking behavioral syndrome. Our results show that individual experience has an unequivocal role in the emergence of behavioral consistency. In this particular case, the development of behavioral consistency was most likely the result of genotype × environment interactions, or with other words, individual variation in behavioral plasticity.     

Differential response to abiotic conditions and predation risk rather than competition avoidance determine breeding site selection by anurans

Co‐existence of species has been a central debate in ecology for decades but the mechanisms that allow co‐existence are still heatedly disputed. The main paradigms have shifted among the importance of competition, predation and abiotic conditions as determinants of community structure. Differential habitat selection is considered to reduce competition and hence allow co‐existence. Our goal was to test hypotheses regarding how breeding site use of a population that was patchily distributed on a dynamic floodplain may facilitate coexistence: 1) do species co‐occur randomly or do they occur more or less often than expected by chance? 2) Do species use the same habitat types in equal proportions or do they use them differentially? 3) If they use habitat types differentially, is this differential use related to abiotic and biotic conditions? 4) Does interspecific competition predict breeding site use or do abiotic conditions and predation risk better predict habitat use? We collected presence/absence (i.e. detection/nondetection) data of egg clutches and larvae of four pond‐breeding anuran species during a two year study at a total of 353 ponds. We used site occupancy models and model averaging techniques to predict breeding site selection in relation to habitat types, abiotic and biotic factors. These parameters were corrected for imperfect detection of species. The rates of co‐occurrence were consistently higher than expected by chance. Species differed in the use of the main habitat types. Habitat types that were used by multiple species were used in a species‐specific manner in relation to both abiotic conditions and predation risk. Species preferred ponds where other species and fish were present. Although niche differentiation in breeding site selection is evident, our results do not support the pervasive role of competition avoidance in governing current breeding site selection. We conclude that differential habitat use and differences in response to abiotic conditions and predation risk can override competitive interactions, thereby facilitating local co‐existence and high species diversity.     

Local predation risk and matrix permeability interact to shape movement strategy

In fragmented landscapes, the reduced connectivity among patches drives the evolution of movement strategies through an increase of transience costs. Reduced movements may further alter heterogeneity in biotic and abiotic conditions experienced by individuals. The joint action of local conditions and matrix permeability may shape emigration decisions. Here, we tested the interactive effects of predation risk and matrix permeability on movement propensity, movement costs and movers’ phenotype in the common toad Bufo bufo. In a full‐crossed experimental design, we assessed the movement propensity of juveniles in three connectivity treatments (from poorly to highly permeable matrix), with or without predation risk in their living patch. We also assessed the relationships between movement propensity and morphological traits (i.e. body and leg length) and how it affected the movement cost (i.e. mass loss). Movement propensity increased in presence of predation risk, while matrix permeability had no effect. However, matrix permeability interacted with predation risk to influence movers’ phenotype and the physiological cost they endured while moving. In particular, a well‐known movement syndrome in toads (i.e. movement propensity positively related to longer legs) depended on the interaction between matrix permeability and predation risk and resulted in differences in mass loss among matrix types. Movers lost more mass on average than residents except when they also displayed longer legs or when they crossed the most permeable matrix in the presence of predation risk. Our results show that matrix permeability shapes the physiological cost of dispersal by changing the identity of individuals moving away from local conditions. As the movers’ phenotype can importantly alter (meta)population dynamics, context‐dependency of dispersal syndromes should be considered in studies predicting the functioning of human‐altered natural systems.     

The Quantitative Genetic Architecture of the Bold-Shy Continuum in Zebrafish,Danio rerio

In studies of consistent individual differences (personality) along the bold-shy continuum, a pattern of behavioral correlations frequently emerges: individuals towards the bold end of the continuum are more likely to utilize risky habitat, approach potential predators, and feed under risky conditions. Here, we address the hypothesis that observed phenotypic correlations among component behaviors of the bold-shy continuum are a result of underlying genetic correlations (quantitative genetic architecture). We used a replicated three-generation pedigree of zebrafish (Danio rerio) to study three putative components of the bold-shy continuum: horizontal position, swim level, and feeding latency. We detected significant narrow-sense heritabilities as well as significant genetic and phenotypic correlations among all three behaviors, such that fish selected for swimming at the front of the tank swam closer to the observer, swam higher in the water column, and fed more quickly than fish selected for swimming at the back of the tank. Further, the lines varied in their initial open field behavior (swim level and activity level). The quantitative genetic architecture of the bold-shy continuum indicates that the multivariate behavioral phenotype characteristic of a “bold” personality type may be a result of correlated evolution via underlying genetic correlations.     

Presumptive environmental effects on body shape of Aplochiton zebra (Pisces, Galaxiidae) in northern Patagonian lakes

The family Galaxiidae exhibits a marked tendency toward morphological variation, particularly in characteristics related to feeding and caudal propulsion. The body shape of Aplochiton zebra from six Andean water bodies was examined and related to diet and to environmental characteristics such as transparency and predation risk. Although adults and larger juveniles showed no inter‐lake dependence in their morphology, smaller juveniles (SL < 40 mm) did show differences in eye diameter and dorsal fin length. Aplochiton zebra juveniles from Lake Puelo, where transparency showed the minimum value, have the largest eyes; those from Lake Futalaufquen with high transparency values have the smallest eyes. No clear relationship to predation risk was established. In Futalaufquen, Puelo and Rivadavia lakes the relationship between the principal components for morphology and for diet indicates, at least in part, that variation in body shape – and particularly traits related to swimming ability – could be related to diet.