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The social environment is a key factor that influences behavioural traits across a wide array of species. Yet, when investigating individual differences in behaviour, studies tend to measure animals in isolation from other conspecifics—even in social species. Surprisingly, whether behavioural traits measured in isolation are predictive of individual-level behaviour when in social groups is still poorly understood. Here, we repeatedly measured risk-taking behaviour (i.e. boldness; 741 total trials) in both the presence and absence of conspecifics in a social lizard, the delicate skink (Lampropholis delicata). Further, we manipulated food availability during group trials to test whether the effect of the social environment on risk-taking behaviour was mediated by competition over resources. Using 105 lizards collected from three independent populations, we found that individual risk-taking behaviour was repeatable when measured in either social isolation or within groups both with and without food resources available. However, lizards that were bolder during individual trials were not also bolder when in groups, regardless of resource availability. This was largely driven by individual differences in social behavioural plasticity, whereby individual skinks responded differently to the presence of conspecifics. Together, this resulted in a rank order change of individual behavioural types across the social conditions. Our results highlight the importance of the social environment in mediating animal personality traits across varying levels of resource availability. Further, these findings suggest that behavioural traits when measured in isolation, may not reflect individual variation in behaviour when measured in more ecologically realistic social groups.

Individuals often differ in how consistently they express their behavior (i.e., behavioural predictability). Recent research suggests that variation behavioral predictability is heritable and has key fitness consequences. We showed that male and female eastern mosquitofish (Gambusia holbrooki) differed in the predictability of their risk-taking behavior. Furthermore, we found that both the direction and magnitude of these sex differences were context specific.Recent research has found that individuals often vary in how consistently they express their behavior over time (i.e., behavioral predictability) and suggested that these individual differences may be heritable. However, little is known about the intrinsic factors that drive variation in the predictability of behavior. Indeed, whether variation in behavioral predictability is sex-specific is not clear. This is important, as behavioral predictability has been associated with vulnerability to predation, suggesting that the predictability of behavioral traits may have key fitness implications. We investigated whether male and female eastern mosquitofish (Gambusia holbrooki) differed in the predictability of their risk-taking behavior. Specifically, over a total of 954 behavioral trials, we repeatedly measured risk-taking behavior with three commonly used assays-refuge-use, thigmotaxis, and foraging latency. We predicted that there would be consistent sex differences in both mean-level risk-taking behavior and behavioral predictability across the assays. We found that risk-taking behavior was repeatable within each assay, and that some individuals were consistently bolder than others across all three assays. There were also consistent sex differences in mean-level risk-taking behavior, with males being bolder across all three assays compared to females. In contrast, both the magnitude and direction of sex differences in behavioral predictability were assay-specific. Taken together, these results highlight that behavioral predictability may be independent from underlying mean-level behavioral traits and suggest that males and females may differentially adjust the consistency of their risk-taking behavior in response to subtle changes in environmental conditions.

Background Globally, there is growing concern over the impacts of pharmaceuticals and drug manufacturing on aquatic animals, and pharmaceuticals are now recognized as contaminants of emerging environmental concern. In recent years, scientists, environmental managers, and policymakers have been interested in using behavioural endpoints for chemical regulation, given their importance for fitness and survival. The body of research on whether and how pharmaceutical exposure alters the behaviour of aquatic animals has grown exponentially, making it difficult to get an overview of the results. With an international spotlight on the management of these environmental threats, synthesizing the currently available data is vital to inform managers and policymakers, as well as highlighting areas where more research is needed. This is a protocol for a systematic evidence map (SEM) and serves as an a priori record of our objectives and methodological decisions. Our objectives are to identify, catalogue, and present primary research articles on the effects of human and veterinary pharmaceuticals on aquatic animal behaviour. Methods The literature search will be conducted using two electronic databases: Web of Science and Scopus, and we will supplement these searches with additional sources. The search string has been developed using a Population–Exposure–Comparison–Outcome (PECO) framework, to capture articles that used an aquatic organism (P, population) to test the effects of a pharmaceutical (E, exposure) on behaviour (O, outcome). Eligible articles must also have a control group (C, comparison). Articles will be screened in two stages, title and abstract, followed by full-text screening before data extraction. Decision trees have been designed a priori to appraise articles for eligibility at both stages of screening. At both stages, screening each article will be completed by two independent reviewers. Study validity will be appraised but not used as a basis for article inclusion. The information extracted from the eligible articles, along with bibliometric data, will be mapped and displayed. All data associated with this SEM will be publicly available through the Open Science Framework (OSF) and a future project webpage.

Within populations, individuals often differ consistently in their average level of behavior (i.e., animal personality), as well as their response to environmental change (i.e., behavioral plasticity). Thus, changes in environmental conditions might be expected to mediate the structure of animal personality traits. However, it is currently not well understood how personality traits change in response to environmental conditions, and whether this effect is consistent across multiple populations within the same species. Accordingly, we investigated variation in personality traits across two ecological contexts in the invasive delicate skink (Lampropholis delicata). Specifically, lizards from three different populations were repeatedly measured for individual activity in group behavioral assays under differing levels of food availability. We found that environmental context had a clear effect on the structure of lizard personality, where activity rates were not repeatable in the absence of food, but were repeatable in the presence of food resources. The difference in repeatability of activity rates across contexts appeared to be largely driven by an increase in among-individual variance when tested in the presence of food resources. However, this was only true for one of the populations tested, with food context having no effect on the expression of personality traits in the other two populations. Our results highlight the important role of environmental context in mediating the structure of animal personality traits and suggest that this effect may vary among populations.

Environments, particularly developmental environments, can generate a considerable amount of phenotypic variation through phenotypic plasticity. Plasticity in response to incubation temperature is well characterised in egg-laying reptiles. However, traits do not always vary independently of one another, and studies encompassing a broad range of traits spanning multiple categories are relatively rare but crucial to better understand whole-organism responses to environmental change, particularly if covariation among traits may constrain plasticity. In this study, we investigated multivariate plasticity in response to incubation across three temperatures in the delicate skink, Lampropholis delicata, and whether this was affected by covariation among traits. At approximately 1 month of age, a suite of growth, locomotor performance, thermal physiology and behavioural traits were measured. Plasticity in the multivariate phenotype of delicate skinks was distinct for different incubation temperatures. Cool temperatures drove shifts in growth, locomotor performance and thermal physiology, while hot temperatures primarily caused changes in locomotor performance and behaviour. These differences are likely due to variation in thermal reaction norms, as there was little evidence that covariation among traits or phenotypic integration influenced plasticity, and there was no effect of incubation temperature on the direction or strength of covariation. While there were broad themes in terms of which trait categories were affected by different incubation treatments, traits appeared to be affected independently by developmental temperature. Comparing reaction norms of a greater range of traits and temperatures will enable better insight into these patterns among trait categories, as well as the impacts of environmental change.

Abstract Developmental environments play a significant role in shaping animal phenotype, including behavior. Within a species, individuals often differ in behavior in a consistent and repeatable way (i.e., demonstrate animal personality). This consistency in behavior can be affected by differences in conditions experienced early in life. It is, however, unclear whether effects of developmental environments on animal personality are driven by changes in within- or between-individual variation. To investigate this, we measured activity, exploration, sociability, and boldness in adult male southern rainforest sunskinks, Lampropholis similis, incubated at either 23 °C or 26 °C, and compared behavioral phenotypes between these incubation treatments. We also compared the behavior of these incubation groups to a cohort of wild-caught skinks to determine whether rearing in captivity also affected the personality of the lizards. Skinks that had been incubated at a higher temperature were more explorative and demonstrated personality in a larger suite of traits compared to lizards incubated at a lower temperature or caught in the wild. These differences among developmental environment were primarily driven by within-individual variation, which tended to be higher among the high incubation treatment. We also found no evidence for a behavioral syndrome in either captive- or wild-reared skinks. Our results suggest the potential for greater behavioral plasticity in skinks incubated at a higher temperature, which may enable them to cope with environmental change, such as climate warming, in the short term. Overall, we show that effects of developmental environment are complex and play a pivotal role in shaping animal personality. Significance statement Experiences during development are expected to influence how animals develop, including their behavior. We tested early environment effects on behavior in adult southern rainforest sunskinks by comparing lizards incubated at different temperatures as well as comparing those reared in the wild with those reared in captive environments. We found that lizards incubated at the higher temperature were more exploratory. Furthermore, both incubation temperature and captivity/wild-rearing had pronounced effects on the consistency of behavior—in different directions for different traits—demonstrating developmental environments have strong effects on animal personality. Such changes in behavioral traits likely have flow-on effects for the animal’s fitness and biotic interactions.

The perception of cues and signals in visual, olfactory and auditory modalities underpins all animal interactions and provides crucial fitness-related information. Sensory organ morphology is under strong selection to optimize detection of salient cues and signals in a given signalling environment, the most well-studied example being selection on eye design in different photic environments. Many dim-light active species have larger compound eyes relative to body size, but little is known about differences in non-visual sensory organ morphology between diurnal and dim-light active insects. Here, we compare the micromorphology of the compound eyes (visual receptors) and antennae (olfactory and mechanical receptors) in representative pairs of day active and dim-light active species spanning multiple taxonomic orders of insects. We find that dim-light activity is associated with larger compound eye ommatidia and larger overall eye surface area across taxonomic orders but find no evidence that morphological adaptations that enhance the sensitivity of the eye in dim-light active insects are accompanied by morphological traits of the antennae that may increase sensitivity to olfactory, chemical or physical stimuli. This suggests that the ecology and natural history of species is a stronger driver of sensory organ morphology than is selection for complementary investment between sensory modalities.

In montane systems, closely related species tend to segregate spatially along elevational gradients. The role of biotic interactions, relative to species physiological requirements, in maintaining these distribution patterns is an important question in spatial ecology. Theory suggests that the role of interspecific competition can be significant in the maintenance of elevation replacement distributions. Despite this, there has been limited work investigating factors beyond thermophysiology in determining ranges in temperate montane species. We investigated agonistic (i.e. aggressive) behaviour in response to a simulated intruder (conspecific versus heterospecific 3D printed models) in two sister species of temperate montane lizard, Liopholis guthega and L. montana, from south-eastern Australia. The two species have similar thermal tolerances at an area of distributional overlap between 1600 and 1700 m above sea level, above which L. montana is replaced by the high elevation specialist L. guthega. We found that response to intruder stimuli differed between the two species, with the high elevation L. guthega actively biting both conspecific and heterospecific models, whereas the lower elevation L. montana, never attacked either model type. Our findings provide evidence of asymmetric agonistic response in the two montane reptile species. These findings have important implications for understanding how biological interactions and behaviour, in addition to thermo-physiological data, might mediate landscape scale distribution patterns both now and as environments change in the future. More broadly, our results are not consistent with the widespread idea that low elevation species will inevitably ‘push’ higher elevation species out, as global warming erodes species’ thermal envelopes.

In many brood-rearing species, suitable nesting resources are needed for nest construction. Here, we used males of a small marine fish, the sand goby, Pomatoschistus minutus, to study the associations between the nest owner's phenotype (i.e. body size), the characteristics of the nesting resource used for nest construction (i.e. resource size and shape) and nest-building behaviour (i.e. eagerness to build a nest and extent of nest elaboration). We found that male body size was associated with nesting resource size and resource architecture in the field, with the smallest males occupying small flat resources and the biggest males occupying large arched resources. In the laboratory, the type of resource occupied in the field had a limited effect on the level of nest elaboration, but not on other nesting behaviours. Large body size, in turn, was associated with preference for larger resources and, in some circumstances, also the level of nest elaboration. Body size did not affect the eagerness to initiate nest building. Furthermore, males chose arched nesting resources more often than those that were flat, and this preference was also reflected under a ‘no-choice’ scenario, based on the time taken for males to initiate nest building. Overall, the results indicate that the importance of male size in nest building is context dependent, while nesting behaviours can also be affected by resource size, resource architecture and, under some circumstances, the nest builder's experience with resource use.

When making decisions, individuals can be influenced by both the range of options available to them and intrinsic factors, such as their own body size or condition. The current understanding of the topic comes mostly from studies of foraging behaviour and mate choice, whereas other fitness-related decisions have been the subject of much less attention. Here, we investigated how the number of available options, along with body size and condition, affect the nesting resource choices of male sand gobies, Pomatoschistus minutus. The results show that resource choices were not affected by additional choice options (i.e. binary versus ternary choice situation) or the body condition of the chooser, whereas resource size, resource type (i.e. whether choices were between arched or flat resources) and body size did have an effect. In particular, while larger nesting resources were chosen more often in most situations, this pattern was stronger among larger males and when the resources had a flat, rather than arched, shape. Indeed, in the case of arched resources, the medium size category was more popular than the smaller and larger ones. Together, the results show that both intrinsic and extrinsic factors can influence important behavioural decisions over resource choice.

Environmental pollution is an increasing problem for wildlife globally. Animals are confronted with many different forms of pollution, including chemicals, light, noise, and heat, and these can disrupt critical biological processes such as reproduction. Impacts on reproductive processes can dramatically reduce the number and quality of offspring produced by exposed individuals, and this can have further repercussions on the ecology and evolution of affected populations. Here, we illustrate how environmental pollutants can affect various components of reproduction in wildlife, including direct impacts on reproductive physiology and development, consequences for gamete quality and function, as well as effects on sexual communication, sexual selection, and parental care. We follow with a discussion of the broader ecological and evolutionary consequences of these effects on reproduction and suggest future directions that may enable us to better understand and address the effects of environmental pollution.

Natural environments are subject to a range of anthropogenic stressors, with pharmaceutical pollution being among the fastest-growing agents of global change. However, despite wild animals living in complex multi-stressor environments, interactions between pharmaceutical exposure and other stressors remain poorly understood. Accordingly, we investigated effects of long-term exposure to the pervasive pharmaceutical contaminant fluoxetine (Prozac) and acute temperature stress on reproductive behaviors and activity levels in the guppy (Poecilia reticulata). Fish were exposed to environmentally realistic fluoxetine concentrations (measured average: 38 or 312 ng/L) or a solvent control for 15 months using a mesocosm system. Additionally, fish were subjected to one of three acute (24 h) temperature treatments: cold stress (18 °C), heat stress (32 °C), or a control (24 °C). We found no evidence for interactive effects of fluoxetine exposure and temperature stress on guppy behavior. However, both stressors had independent impacts. Fluoxetine exposure resulted in increased male coercive copulatory behavior, while fish activity levels were unaffected. Under cold-temperature stress, both sexes were less active and males exhibited less frequent reproductive behaviors. Our results demonstrate that long-term exposure to a common pharmaceutical pollutant and acute temperature stress alter fundamental fitness-related behaviors in fish, potentially shifting population dynamics in contaminated ecosystems.

Caudal autotomy, the voluntary shedding of a tail, is a last-ditch strategy used by many lizard species to escape from predators. There are several costs associated with caudal autotomy that may cause lizards to change their behaviour during tail regeneration. These behavioural changes may be dependent upon individual differences in response to autotomy (e.g. trait or state-dependent differences) and/or the degree of tail loss, as many lizards have the capacity to only partially shed their tail which probably entails fewer costs relative to complete autotomy. However, no study, to our knowledge, has considered how caudal autotomy, or the extent of autotomy, affects individual behavioural variation. Accordingly, we investigated the effects of both partial and complete tail loss on individual behavioural variation in delicate skinks, Lampropholis delicata. We found that lizards that experienced complete tail loss, on average, became less active and explorative and had much slower sprint speeds following autotomy. These lizards also became more predictable and consistent in their behaviour, exhibiting a notable decrease in their within-individual behavioural variance. In contrast, we did not see any significant behavioural effects in lizards that experienced partial tail loss. We also found a positive among-individual correlation between activity/exploration and neophilia, but tail loss had no effect on the structure of this syndrome. Our results suggest that complete tail loss may impose effects on traits more closely associated with locomotion and predator escape ability, while also constraining an individual's capacity for differential behavioural expression.

Adaptive radiations have proven important for understanding the mechanisms and processes underlying biological diversity. The convergence of form and function, as well as admixture and adaptive introgression, are common in adaptive radiations. However, distinguishing between these two scenarios remains a challenge for evo-lutionary research. The Midas cichlid species complex (Amphilophus spp.) is a prime example of adaptive radiation, with phenotypic diversification occurring at various stages of genetic differentiation. One species, A. labiatus, has large fleshy lips, is as-sociated with rocky lake substrates, and occurs patchily within Lakes Nicaragua and Managua. By contrast, the similar, but thin- lipped, congener, A. citrinellus, is more com-mon and widespread. We investigated the evolutionary history of the large- lipped form, specifically regarding whether the trait has evolved independently in both lakes from ancestral thin- lipped populations, or via dispersal and/or admixture events. We collected samples from distinct locations in both lakes, and assessed differences in morphology and ecology. Using RAD-seq, we genotyped thousands of SNPs to measure population structure and divergence, demographic history, and admixture. We found significant between-species differences in ecology and morphology, local intraspecific differences in body shape and trophic traits, but only limited intraspe-cific variation in lip shape. Despite clear ecological differences, our genomic approach uncovered pervasive admixture between the species and low genomic differentiation, with species within lakes being genetically more similar than species between lakes. Taken together, our results suggest a single origin of large-lips, followed by pervasive admixture and adaptive introgression, with morphology being driven by local ecologi-cal opportunities, despite ongoing gene-flow., Funding was also provided by a Monash University travel grant (to WS) and from the SYNTHESYS Project (http://www.synthesys.info/) financed by the European Community Research Infrastructure Action under the FP7 "Capacities" Program (to TKL and MB).

Nest predation has a large impact on reproductive success in many taxa. Defending offspring from would-be predators can also be energetically and physiologically costly for parents. Thus, to maximize their reproductive payoffs, individuals should adjust their reproductive behaviors in relation to the presence of nest predators. However, effects of nest predator presence on parental behaviors across multiple reproductive contexts remain poorly understood, particularly in non-avian taxa. We ran a series of experiments to test how the presence of an egg predator, the invasive rockpool shrimp, Palaemon elegans, influences male reproductive decisions and egg survival in a species of fish with exclusive paternal care, the three-spined stickleback, Gasterosteus aculeatus. We found that, in the presence of shrimp, male sticklebacks were less likely to build a nest, invested less in territory defense against an intruder, and tended to fan eggs in their nest less and in shorter bouts, but did not alter their investment in courtship behavior. The predator’s presence also did not affect egg survival rates, suggesting that males effectively defended their brood from the shrimp. These results show that reproducing individuals can be highly responsive to the presence of nest predators and adjust their behavioral decisions accordingly across a suite of reproductive contexts.

Behavior-modifying drugs, such as antidepressants, are increasingly being detected in waterways and aquatic wildlife around the globe. Typically, behavioral effects of these contaminants are assessed using animals tested in social isolation. However, for group-living species, effects seen in isolation may not reflect those occurring in realistic social settings. Furthermore, interactions between chemical pollution and other stressors, such as predation risk, are seldom considered. This is true even though animals in the wild are rarely, if ever, confronted by chemical pollution as a single stressor. Here, in a 2 year multigenerational experiment, we tested for effects of the antidepressant fluoxetine (measured concentrations [±SD]: 42.27 ± 36.14 and 359.06 ± 262.65 ng/L) on shoaling behavior in guppies (Poecilia reticulata) across different social contexts and under varying levels of perceived predation risk. Shoaling propensity and shoal choice (choice of groups with different densities) were assessed in a Y-maze under the presence of a predatory or nonpredatory heterospecific, with guppies tested individually and in male-female pairs. When tested individually, no effect of fluoxetine was seen on shoaling behavior. However, in paired trials, high-fluoxetine-exposed fish exhibited a significantly greater shoaling propensity. Hence, effects of fluoxetine were mediated by social context, highlighting the importance of this fundamental but rarely considered factor when evaluating impacts of environmental pollution.

The introduction of species outside their native range is an insidious form of human-induced environmental change, with mounting evidence that behaviour, either through plastic behavioural responses or adaptive changes, can play a vital role in mediating invasion success. In particular, when species invade non-native habitats, they often leave behind native predators. Altered predator assemblages may then result in changes to antipredator responses overtime. Here, we capitalise on the well-characterised invasion history of an Australian reptile, the delicate skink, Lampropholis delicata, to investigate differences in antipredator responses between an invasive island population (Lord Howe Island) and its original mainland source (Coffs Harbour) following 40 generations of isolation. Specifically, we examined the responses of invasive and native skinks to scent cues taken from huntsman spiders, Heteropoda sp., a predator present in both populations, and red-bellied black snakes, Pseudechis porphyriacus, a predator absent from the invasive range. We measured the time skinks took to emerge from a shelter site and subsequent basking and foraging behaviours in the absence and presence of each predator scent. We did not detect any differences in responses between native and invasive skinks, although predator scent affected foraging behaviour. In a separate experiment, lizards were faced with a simulated bird strike and had the choice of retreating under a snake-scented or unscented shelter. When faced with such a threat, we found that skinks did not avoid snake-scented shelters. We also measured the activity and exploratory behaviour of each skink prior to exposure to predator cues, finding that increased activity and exploration appears to be linked to reduced antipredator behaviour for invasive but not native skinks. Contrary to our initial predictions, our results suggest that the relaxation of pressure from native predators may not necessarily translate to changes in key antipredator responses in invasive species, even after 40 generations of isolation. Human movement introduce species into novel areas, where they are confronted with a suite of ecological challenges that must be navigated, including changes to predator assemblages, in order to successfully establish and become invasive. Altered predator assemblages encountered by invasive species may, in turn, result in changes to, or loss of, antipredator responses over time. We studied such a scenario in the delicate skink, an Australian lizard that has been repeatedly introduced to new areas. We compared the antipredator behaviour of skinks from an invasive island population to skinks from their original mainland source. We found that despite 40 generations of isolation, invasive skinks do not differ from native skinks in their antipredator behaviour. However, we found that greater activity and exploration levels had become linked to reduced antipredator behaviour in invasive but not native skinks.

Biological invasions are a prominent example of human-induced environmental change that pose a significant threat to worldwide biodiversity. Recent evidence suggests that behavioural traits play a key role in mediating invasion success. However, little research has investigated how rapidly behavioural traits can change during the initial stages of invasion. We investigated the influence of invasion on behaviour in a recent aquatic invader, the Siamese fighting fish (Betta splendens), in northern Australia. These fish represent a recent introduction (ca. 2010) and are thought to be descended from ornamental varieties released into the wild from the aquarium trade. Using fish reared under captive conditions, we measured differences in three ecologically relevant behaviours (activity, foraging, and aggression) across invasive and domestic fighting fish. We found that fish descended from the recent invasive population were more active and consumed fewer food items than their domestic counterparts. Furthermore, foraging latency was repeatable in invasive, but not domestic fish, and this seemed to be driven by an increase in among-individual variation in the invasive population. Finally, while we detected a positive relationship between activity and number of food items eaten in domestic fish, this relationship was absent in the invasive population, suggesting that invasion may have disrupted this behavioural syndrome. Our results highlight that invasion can alter ecologically important behavioural traits and behavioural syndromes, even during the initial stages of invasion, and emphasise the importance of incorporating behaviour into our understanding of invasion biology. Alien species must rapidly adapt to novel environmental conditions in order to establish a successful invasive population. As behaviour mediates how organisms interact with their environment, behavioural traits may play a key role in facilitating invasion success. We investigated rapid changes in behavioural traits in a recently introduced (ca. 2010) ornamental fish, the Siamese fighting fish. We found that invasive fish differed from their domestic source population in two key behavioural traits—activity and foraging behaviour. Furthermore, we extend previous work by showing that invasion not only causes changes in average-level behavioural traits but can also result in changing patterns of behavioural variation and repeatability in newly established populations. Overall, our findings highlight that invasion can induce shifts in ecologically relevant behaviours, even during the early, crucial stages of invasion.

Rohan Brooker and Bob Wong introduce the ways animals conceal themselves using non-visual sensory stimuli.

Studying food webs across contrasting abiotic conditions is an important tool in understanding how environmental variability impacts community structure and ecosystem dynamics. The study of extreme environments provides insight into community‐wide level responses to environmental pressures with relevance to the future management of aquatic ecosystems. In the western Lake Eyre Basin of arid Australia, there are two characteristic and contrasting aquatic habitats: springs and rivers. Permanent isolated Great Artesian Basin springs represent hydrologically persistent environments in an arid desert landscape. In contrast, hydrologically variable river waterholes are ephemeral in space and time. We comprehensively sampled aquatic assemblages in contrasting ecosystem types to assess patterns in community composition and to quantify food web attributes with stable isotopes. Springs and rivers were found to have markedly different invertebrate communities, with rivers dominated by more dispersive species and springs associated with species that show high local endemism. Qualitative assessment of basal resources shows autochthonous carbon appears to be a key basal resource in both types of habitat, although the particular sources differed between habitats. Food‐web variables such as trophic length, trophic breadth, and community isotopic niche size were relatively similar in the two habitat types. The basis for the similarity in food‐web structure despite differences in community composition appears to be broader isotopic niches for predatory invertebrates and fish in springs as compared with rivers. In contrast to published theory, our findings suggest that the food webs of the hydrologically variable river sites may show less dietary generalization and more compact food‐web modules than in springs., We analyzed aquatic assemblages in the western Lake Eyre Basin of arid Australia, using stable isotope analysis and measures of community composition across two characteristic and contrasting aquatic habitats: springs and rivers. Springs and rivers were found to have markedly different invertebrate communities, but general food‐web variables such as trophic length, trophic breadth, and community isotopic niche size were relatively similar in the two habitat types despite some subtle differences in the isotopic niche of specific functional groups and basal carbon sources.

Reproductive sciences have made major contributions to human health, livestock production and environmental management in the past and will continue to do so in future. In collaboration with other disciplines, reproductive scientists can provide scientifically valid information that will allow the rational development of policies on topics such as declining fertility in men and women, livestock breeding efficiencies, climate change, pest animal control, wildlife management and environmental influences. It is imperative that the reproductive sciences are recognised by the community and policy makers as important contributors to future health and welfare of animals, humans and the planet if these potential benefits are to be captured and utilised. Reproductive Health Australia (RHA) was launched recently to advocate for reproductive biology as a national health, economic and social priority. This short review provides a snapshot of why it is imperative that reproductive science receives the recognition that is due to it and provides examples of how it can contribute to the future of the planet.

Background: Artificial light at night (ALAN), has increased dramatically over the past two centuries and is linked to demonstrable shifts in a range of behaviours across diverse animal taxa. This systematic map will collate and synthesise the documented effects of ALAN on animal behaviour and fitness, identify gaps in the literature, inform future research and provide the basis for a decision-making tool for informing policy makers. Methods: This systematic map will summarise and examine all available evidence on the effects of ALAN on animal behaviour and ensuing fitness effects. All documented changes to behaviour in animals (excluding humans), will be included and both peer reviewed primary and grey literature will be searched. Searches will be conducted in academic journal databases, online search engines, and specialist websites. Articles will be screened for inclusion in the systematic map at title, abstract and full-text levels and will then be critically appraised for study robustness and validity. Data from studies included in the review will then be extracted and coded according to categories informed by consultation with Stakeholders. Data will be summarised, where possible, in a quantitative manner, accompanied with a descriptive overview. Future avenues for research and specific questions suitable for a systematic literature review will be formulated.

Pharmaceutical contaminants are being detected with increased frequency in organisms and ecosystems worldwide. This represents a major environmental concern given that various pharmaceuticals act on drug targets that are evolutionarily conserved across diverse taxa, are often persistent in the environment, and can bioconcentrate in organisms and bioaccumulate in food chains. Despite this, relatively little is known about the potential for pharmaceutical contaminants to affect animal behaviour, especially across multiple fitness-related contexts. Here, we investigated impacts of 21-day exposure of wild-caught male eastern mosquitofish (Gambusia holbrooki) to a field-realistic level of the veterinary pharmaceutical 17β-trenbolone-a growth-promoting steroid used extensively in beef production worldwide and a potent androgenic endocrine disruptor repeatedly detected in surface waters affected by livestock effluent run-off. First, we examined male boldness, activity, and exploratory behaviour in a novel environment (maze arena) and found no significant effect of 17β-trenbolone exposure. Second, the same males were tested in a reproductive assay for their tendency to associate with a stimulus (unexposed) female behind a partition. Exposed males exhibited reduced association behaviour, taking longer to first associate with, and spending less time within close proximity to, a female. Third, all males were assayed for sperm function (computer-assisted sperm analysis, sperm viability) or quantity (total sperm count) and, although no significant main effects of 17β-trenbolone were seen on sperm traits, exposure altered the relationship between male morphology and sperm function. Lastly, morphological traits were assessed and exposed males were found to have, on average, increased mass relative to length. In combination, these results demonstrate that exposure to a field-realistic level of 17β-trenbolone can produce subtle but important trait alterations in male fish-including context-specific behavioural changes, disruption of key sperm function trade-offs, and altered morphology-with potential impacts on exposed wildlife.

Pharmaceutical contamination is an increasing problem globally. In this regard, the selective serotonin reuptake inhibitors (SSRIs)-a group of antidepressants-are particularly concerning. By disrupting the serotonergic system, SSRIs have the potential to affect ecologically important behaviors in exposed wildlife. Despite this, the nature and magnitude of behavioral perturbations resulting from environmentally relevant SSRI exposure among species is poorly understood. Accordingly, we investigated the effects of two field-realistic levels of the SSRI fluoxetine (61 and 352 ng/L) on sociability and anxiety-related behaviors in eastern mosquitofish ( Gambusia holbrooki) for 28 days. Additionally, we measured whole-body tissue concentrations of fluoxetine and norfluoxetine. We found that fluoxetine altered anxiety-related behavior but not sociability. Specifically, female fish showed reduced anxiety-related behavior at the lower treatment level, while males showed an increase at the higher treatment level. In addition, we report a biomass-dependent and sex-specific accumulation of fluoxetine and norfluoxetine, with smaller fish showing higher relative tissue concentrations, with this relationship being more pronounced in males. Our study provides evidence for nonmonotonic and sex-specific effects of fluoxetine exposure at field-realistic concentrations. More broadly, our study demonstrated that neuroactive pharmaceuticals, such as fluoxetine, can affect aquatic life by causing subtle but important shifts in ecologically relevant behaviors.

The critical thermal limits of organisms and the thermal sensitivity of their performance tend to vary predictably across latitudinal gradients. There has been comparatively less investigation into variation in thermal biology with elevation, despite similar gradients in environmental temperatures. To redress this, we examined critical thermal limits (CTmin and CTmax), thermal sensitivity of locomotor performance, and shelter site attributes, in three lizard species that replace one another along a contiguous elevation gradient in south-eastern Australia. The species examined consisted of a highland specialist, Liopholis guthega, mid-elevation species, Liopholis montana, and lowland species, Liopholis whitii. We found similar habitat attributes between the species, but L. guthega predominantly occurred in open habitat, which might reflect a strategy for maximizing exposure to insolation. We found intraspecific variation in lizard thermal traits, most notably in cold tolerance of L. guthega and in both heat and cold tolerance of L. whitii, suggesting population-specific variables acting on thermal physiology rather than a species distribution maintained by distinct thermal tolerances. This study represents one of the few examinations of thermal trait variability within and between species with elevation in a temperate system and provides evidence for thermal physiology driven by adaptation and/or physiological plasticity to local conditions.

With the ability to resist biodegradation and exert therapeutic effects at low concentrations, pharmaceutical contaminants have become environmental stressors for wildlife. One such contaminant is the anxiolytic oxazepam, a psychoactive pharmaceutical that is frequently detected in surface waters globally. Despite growing interest in understanding how wildlife respond to anxiolytics, synergistic effects of pharmaceuticals and other abiotic (e.g. temperature) and biotic (e.g. predation risk) stressors remain unclear. Here, using a multi-stressor approach, we investigated effects of 7-day oxazepam exposure (6.5 μg/L) on anxiety-related behaviours in juvenile European perch (Perca fluviatilis). The multi-stressor approach was achieved by exposing perch to oxazepam at two temperatures (10 °C and 18 °C), and at two predation risk regimes-generated using chemical cues from the northern pike (Esox lucius). Our exposures resulted in a successful uptake of the drug from the water, i.e., oxazepam was measured in perch muscle tissue at 50 ± 17 ng/g (mean ± SD). We found significant oxazepam-induced effects on boldness, with 76.7% of the treated fish entering the white background (i.e. 'exposed' area where exposure to presumed risks are higher) within the first 5 min, compared to 66.6% of the control fish. We also found a significant effect of temperature on total time spent freezing (i.e. staying motionless). Specifically, fish in the low temperature treatments (oxazepam, predation) froze for longer than fish in high temperatures. Our multi-stressor study is the first to uncover how anxiety-related behaviours in wild juvenile fish are altered by changes in water temperature and perceived predation risk. Importantly, our findings highlight the need to focus on multiple stressors to improve understanding of how organisms not only survive, but adapt to, human-induced environmental change.

A key goal in the study of animal personalities is to determine their adaptive potential and importance for behavioral evolution. Behavioral syndromes are evolutionarily intriguing because they suggest that an adaptive change in one behavior requires a concomitant shift in another. Within species, behavioral syndromes might be evolutionarily constrained by intrinsic mechanisms that restrict behaviors from evolving independently. Alternatively, behavioral correlations might easily be decoupled over short evolutionary time scales due to variation in selective pressures between environments. In this regard, comparative studies that explore differences in diverse aspects of personality between geographically distinct populations can provide valuable insights into the evolutionary processes acting on different behavioral tendencies. Accordingly, we investigated how behavioral types and behavioral syndromes differed across four geographically distinct populations of the delicate skink, Lampropholis delicata. We found strong evidence of mean trait-level variation in activity, exploration, and boldness across populations, suggesting adaptation to local environmental conditions. Similarly, we found that within-population correlations involving boldness varied substantially between populations. However, we did find a consistent within- and among-population correlation between activity and exploration, suggesting that this behavioral syndrome is relatively stable and could explain behavioral divergence in activity and exploration between populations. We suggest that there may be thermal physiological mechanisms that could be limiting the adaptive potential of an activity-exploration correlation in the delicate skink. Broadly, we argue that some behavioral correlations may be more adaptive than others, and that this should be more regularly considered within the animal personality framework. Animals have personalities which have important consequences for individual survival and population dynamics. We compared personality traits between 4 populations of a lizard to understand how different personalities might evolve. Populations expressed markedly diverse personalities, but we did find in all populations that lizards which were most active were also the most explorative. Our results suggest that some personalities are mostly shaped by environmental factors, whereas others are mediated by internal constraints like physiology.

For decades, we have known that chemicals affect human and wildlife behavior. Moreover, due to recent technological and computational advances, scientists are now increasingly aware that a wide variety of contaminants and other environmental stressors adversely affect organismal behavior and subsequent ecological outcomes in terrestrial and aquatic ecosystems. There is also a groundswell of concern that regulatory ecotoxicology does not adequately consider behavior, primarily due to a lack of standardized toxicity methods. This has, in turn, led to the exclusion of many behavioral ecotoxicology studies from chemical risk assessments. To improve understanding of the challenges and opportunities for behavioral ecotoxicology within regulatory toxicology/risk assessment, a unique workshop with international representatives from the fields of behavioral ecology, ecotoxicology, regulatory (eco)toxicology, neurotoxicology, test standardization, and risk assessment resulted in the formation of consensus perspectives and recommendations, which promise to serve as a roadmap to advance interfaces among the basic and translational sciences, and regulatory practices.

Although many pharmaceutical compounds (and their metabolites) can induce harmful impacts at the molecular, physiological and behavioural levels, their underlying mechanistic associations have remained largely unexplored. Here, we utilized RNA-Seq to build a whole brain transcriptome profile to examine the impact of a common endocrine disrupting pharmaceutical (17α-ethinyl estradiol, EE2) on reproductive behaviour in wild guppies (Poecilia reticulata). Specifically, we annotated 16,791 coding transcripts in whole brain tissue in relation to the courtship behaviour (i.e. sigmoid display) of EE2 exposed (at environmentally relevant concentration of 8 ng/L for 28-days) and unexposed guppies. Further, we obtained 10,960 assembled transcripts matching in the non-coding orthologous genomes. Behavioural responses were assessed using a standard mate choice experiment, which allowed us to disentangle chemical cues from visual cues. We found that a high proportion of the RNAseq reads aligned back to our de novo assembled transcriptome with 80.59% mapping rate. Behavioural experiments showed that when males were presented only with female visual cues, there was a significant interaction between male treatment and female treatment in the time spent in the preference zone. This is one of the first studies to show that transcriptome-wide changes are associated with the reproductive behaviour of fish: EE2 exposed male guppies that performed high levels of courtship had a gene profile that deviated the most from the other treatment groups, while both non-courting EE2 and control males had similar gene signatures. Using Gene Ontology pathway analysis, our study shows that EE2-exposed males had gene transcripts enriched for pathways associated with altered immunity, starvation, altered metabolism and spermatogenesis. Our study demonstrates that multiple gene networks orchestrate courting behaviour, emphasizing the importance of investigating impacts of pharmaceuticals on gene networks instead of single genes.

Ecological specialisation is hypothesised to play a major role in the evolution of phenotypic diversity, especially following the colonisation of novel habitats. For example, cichlid fishes provide some of the most remarkable evidence for rapid ecological diversification. Here, we capitalised on a recently (≤ 40 years ago) introduced population of red devils (Amphilophus labiatus) in Australia to investigate adaptive phenotypic responses to a novel environment. We used stomach content analyses, morphometrics and laboratory experiments to test for covariation between diet and size of an important trophic trait, lip size. We found that, while maximum lip size in the study population was smaller than in the species’ natural range, the proportions of algae, insects and fish remains in the diet covaried with lip size. However, contrary to predictions, we found no evidence for lip development to be plastic under laboratory conditions in relation to substrate complexity or food manipulation, nor did we find any relationship between lip morphology and feeding performance in adults. Single nucleotide polymorphism data, in turn, suggested that the introduced population has reduced standing genetic variation, which potentially influences both phenotypic plasticity and diversity, in comparison to native populations. Together, the results suggest that morphological variation in a key trophic trait can respond rapidly to diet in a novel environment, despite reduced genetic diversity in the population., This study was funded by a Holsworth Wildlife Endowment, and a Linnean Society of New South Wales Small Research Grant, both awarded to WS. The research alsoreceived support from the SYNTHESYS Project (https://www.synthesys.info/), which is financed by European Community Research Infrastructure Action under the FP7 ‘‘Capacities’’Program (to TKL and MB).

Animals raised in captivity go through drastically different life experiences compared with those raised in the wild. The captive environment is usually characterised by highly stable conditions and limited social interactions. Such early developmental environment, alone and interacting with genes, can have long-lasting effects on cognitive performance. By testing pairs of mothers and offspring delicate skinks, Lampropholis delicata, we investigated how being raised in a captive environment shapes spatial learning. Additionally, with this design, we were able to evaluate the additive genetic component and strength of genetic effects in this lizard species. Using a Y-maze task, we compared the spatial learning abilities of wild-caught adult female (mothers) delicate skinks, to their captive-born and raised sexually mature offspring. We found that more mothers completed the task and showed shorter latencies compared with offspring who took longer to complete the maze. The offspring performance did not appear to correlate with their mothers’ performance, indicating little narrow-sense heritability. Furthermore, offspring performance was neither affected nor predicted by their mothers’ performance, indicating a limited overall genetic effect. Our results suggest that early life experiences in a captive environment may have a hindering effect on cognitive performance. How important are environmental effects compared with genetics on the development of learning abilities in non-human animals? Studying mother-offspring skink pairs, we show that wild-born mothers outperformed their captive-born offspring in a spatial learning task. We further show that offspring performance in the task was neither explained nor predicted by their mothers’ performance. We suggest that conditions during early-life stages shape spatial learning more than genetics, and stable captive conditions may have a negative effect on the development of spatial learning.

International audience; A key challenge in invasion biology is identifying characteristics that allow some species to be repeatedly successful at invading novel environments. Invasions can often be disproportionately driven by a single sex, with differences in behavioural mechanisms between the sexes potentially underlying sex-biased invasiveness. Here, we took an animal personality approach to study the behaviour of two repeatedly successful congeneric invasive species, the western mosquitofish, Gambusia affinis, and the eastern mosquitofish, Gambusia holbrooki. In each species, we investigated whether males and females shared common personality traits (i.e. behavioural types and behavioural syndromes), with the aim of identifying possible behavioural mechanisms that could help explain why mosquitofish invasions are often characterised by sex-biased founder populations. We found sex-dependent personality, although sex differences varied between species. Specifically, male G. affinis were bolder and less social than female G. affinis, whereas we found no behavioural type differences between the sexes in G. holbrooki. We also found a consistent correlation between boldness and exploration in both sexes within G. affinis, but this correlation was weak in G. holbrooki. Finally, exploration was also correlated with sociability in male G. affinis, but not in females. Our results suggest that behavioural tendencies may diverge, both among species and between the sexes, because of adaptation experienced during different invasion pathways. Broadly, identifying the behavioural mechanisms that predict an individual's 'invasiveness' may be difficult to tease apart between species because each invasion is characterised by different abiotic and biotic interactions that likely require different suites of behaviours. Future studies are needed to elucidate whether, in fact, personality variation between the sexes can mediate the occurrence of sex-biased invasions.

Worldwide, biologically active pharmaceuticals, such as psychoactive drugs, are routinely detected in aquatic ecosystems. In this regard, selective serotonin reuptake inhibitors (SSRIs), a class of antidepressant, are of major environmental concern. Through targeted action on evolutionarily conserved physiological pathways, SSRIs could alter ecologically important behaviours in exposed organisms. Here, using two field-realistic dosages (measured concentrations: 18 and 215 ng/L) of the SSRI fluoxetine (Prozac), we examined the effects of exposure on anxiety-related behaviours in wild-caught female mosquitofish, Gambusia holbrooki. Anxiety-related behaviour was assessed using a light/dark transition test, with the swimming activity of fish recorded under two alternating light conditions, complete darkness and bright light, with the shift in light condition used to induce an anxiety-like response. Fluoxetine exposure resulted in a nonmonotonic decrease in anxiety-related behaviour (i.e. nonlinear with dose), with fish in the low-fluoxetine treatment being less responsive to shifts in light condition compared to unexposed fish. There was no such difference between unexposed and high-exposed fish. Further, we detected a significant interaction between exposure treatment and fish weight on general swimming activity, suggesting the presence of a mass-specific effect of fluoxetine. More broadly, contaminant-induced disruption of animal behaviour—as documented here—could have wide-reaching effects on population-level fitness.

The pace-of-life syndrome (POLS) suggests that behavioral traits are correlated and integrate within a fast–slow physiological continuum. At the fast extreme, individuals having higher metabolic rates are more active, exploratory, and bold with the opposite suite of traits characterizing those at the slow physiological extreme. A recent framework suggests that behavioral types may also differ consistently in their cognitive style. Accordingly, we propose that cognition could be further incorporated into the POLS framework comprised of behavioral and thermal physiological traits. Under this premise, fast behavioral types having high thermal traits are predicted to acquire a novel task faster but at the cost of accuracy while slow behavioral types with low thermal traits would be more attentive, responding to cues at a slower rate leading to higher accuracy and flexibility. This was tested by measuring physiological and behavioral traits in delicate skinks (Lampropholis delicata) and testing their learning ability. Correlations were detected between cognition and behavior but not thermal physiology. Contrary to our predictions, individual positioning along these axes opposed our predicted directions along the fast–slow continuum. Fast lizards preferring lower body temperatures expressed higher activity, exploration, sociality, and boldness levels, and learned the discrimination learning task at a slower rate but made the most errors. Additionally, modelling results indicated that neither thermal physiology, behavior, or their interaction influenced cognitive performance. Although the small number of animals completing the final stages of the learning assays limits the strength of these findings. Thus, we propose that future research involving a greater sample size and number of trials be conducted so as to enhance our understanding into how the integration of cognitive style, behavior, and physiology may influence individual fitness within natural populations.

Female ornaments are a rare occurrence in nature. One explanation for this is that female ornaments are costly to produce and maintain and, therefore, females must trade-off resources related to reproduction to promote ornament expression. Here, we investigate the potential trade-off between female ornamentation and fecundity in the sex-role reversed, wide-bodied pipefish, Stigmatopora nigra. We measured two components of the female ornament, body width and stripe thickness, and tested the relationship between these ornaments and female fecundity and the mean egg size. Both body width and stripe thickness were strongly and positively related to female body size. After controlling for the influence of body size, we found no evidence of a cost of belly width or stripe thickness on female fecundity. Rather, females that have larger ornaments have higher fecundity and thus a greater relative fitness advantage. However, larger females suffered a slight decrease in egg size, consistent with a potential trade-off between egg size and body size, although no relationship between egg size and ornaments was observed. Our results suggest that larger S. nigra females accurately advertise their reproductive value to males, and underscore the importance of investigating the potential mechanisms that promote and maintain honesty of female ornaments.

The environmental impact of endocrine-disrupting chemicals (EDCs)—compounds that interfere with endocrine system function at minute concentrations—is now well established. In recent years, concern has been mounting over a group of endocrine disruptors known as hormonal growth promotants (HGPs), which are natural and synthetic chemicals used to promote growth in livestock by targeting the endocrine system. One of the most potent compounds to enter the environment as a result of HGP use is 17β-trenbolone, which has repeatedly been detected in aquatic habitats. Although recent research has revealed that 17β-trenbolone can interfere with mechanisms of sexual selection, its potential to impact sequential female mate choice remains unknown, as is true for all EDCs. To address this, we exposed female guppies (Poecilia reticulata) to 17β-trenbolone at an environmentally relevant level (average measured concentration: 2 ng/L) for 21 days using a flow-through system. We then compared the response of unexposed and exposed females to sequentially presented stimulus (i.e., unexposed) males that varied in their relative body area of orange pigmentation, as female guppies have a known preference for orange colouration in males. We found that, regardless of male orange pigmentation, both unexposed and exposed females associated with males indiscriminately during their first male encounter. However, during the second male presentation, unexposed females significantly reduced the amount of time they spent associating with low-orange males if they had previously encountered a high-orange male. Conversely, 17β-trenbolone-exposed females associated with males indiscriminately (i.e., regardless of orange colouration) during both their first and second male encounter, and, overall, associated with males significantly less than did unexposed females during both presentations. This is the first study to demonstrate altered sequential female mate choice resulting from exposure to an endocrine disruptor, highlighting the need for a greater understanding of how EDCs may impact complex mechanisms of sexual selection.

Defending offspring provides fitness benefits to parents, but is costly. To moderate costs, parents should adjust aggressive responses to the threat posed by different species entering their territory. However, few studies have experimentally tested behavioral adjustments in response to the threat posed by different types of intruders, particularly in the field, and in environments with an array of heterospecific intruders. Here, using a biparental cichlid, the poor man’s tropheus (Hypsophrys nematopus), we investigated whether males and females in the wild invest equally into offspring defense and what impact the absence of a partner might have on the quality of offspring defense provided by a solitary parent. In a separate experiment, we assessed responses of breeding pairs to 3 common heterospecific intruders that pose different levels of threat to the breeding pair and their brood. We found that both paired and unpaired females invested significantly more into territorial aggression than males. However, unpaired females were unable to fully compensate for the absence of their partner, with intruders left to venture closer to their offspring. Furthermore, we show that breeding pairs can readily discriminate between heterospecific intruders, with pairs responding quicker and more aggressively towards species that posed a greater potential threat. Our results demonstrate that biparental species can have extensive behavioral flexibility in their aggressive responses towards intruders, even in environments with a high frequency of territory incursion. The quality of territorial defense can nevertheless be compromised if one parent is left to defend the brood alone.

1. Physiology and temperature can both have a profound influence on behaviour and metabolism. Despite this, thermal physiology has rarely been considered within the animal personality framework, but could be an inherent mechanism maintaining consistent individual differences in behaviour, particularly in species that need to thermoregulate (i.e. ectotherms). 2. Here, we present evidence for a thermal-behavioural syndrome and detail how it is linked to variation in habitat selection in an Australian lizard, the delicate skink, Lampropholis delicata. 3. We predicted that individuals would occur along a cold-hot continuum – analogues to the slow-fast continuum proposed by the pace-of-life hypothesis - whereby an individual’s placement along a thermal physiological axis will correspond with their placement along a personality axis. We first tested the thermal-behavioural syndrome by measuring the thermal preferences and optimal performance temperature of individual skinks and linking it to their activity, exploratory, social and boldness behaviours. 4. In line with our predictions, we found that individuals with a ‘hot’ thermal type performed optimally at higher temperatures, had faster sprint speeds and were more active, explorative and bold relative to ‘cold’ thermal types. 5. We then monitored each individual’s habitat selection within an artificial environment containing three microhabitats differing in their thermal characteristics. 6. We found that an individual’s thermal type mediated their use of habitat, in which ‘hot’ individuals utilised a hotter microhabitat more regularly than both ‘cold’ and ‘intermediate’ thermal types, suggesting that the thermal-behavioural syndrome could drive ecological niche partitioning in this species. 7. We envisage that the thermal-behavioural syndrome concept is likely to extend to other study systems, particularly to ectothermic organisms that rely heavily on behavioural thermoregulation to maintain optimal body temperature.