Search for: All records

Social experiences can shape adult behavior and cognition. Here, we use El Abra swordtails (Xiphophorus nigrensis) to assess how life-long experience with different male mating tactics shapes coercion evasion ability and female spatial cognition. We raised females from birth to adulthood in environments that varied by male mating tactic: coercers only, courtship displayers only, coercers and displayers together, mixed-strategists, and female only. In adulthood, we tested females’ behavioral responses to a coercive male and spatial cognition in a maze. Females reared with only displayers were significantly worse at distancing themselves from the coercive male than females raised with coercers and displayers and females raised with only coercers. Females raised with a single mating tactic (either courtship display or coercion) exhibited significantly higher accuracy in the spatial maze than females from other rearing groups, and showed significant reduction in total errors (courtship display group) or latency to reward (coercion group) over successive trials. These more predictable environments (one tactic), and not the more complex environments (two tactics), showed evidence for spatial learning. The results are discussed in light of the existing literature on two components of environmental change (environmental predictability and the certainty with which cues predict the best behavioral response) and their effect on the development of cognitive abilities. 

Sexual selection is a powerful diversifier of phenotype, behavior and cognition. Here we compare cognitive-behavioral traits across four reproductive phenotypes (females and three alternative males) of wild-caught ocellated wrasse ( Symphodus ocellatus ). Both sex and alternative male phenotypes are environmentally determined with sex determination occuring within the first year, and males transition between alternative phenotypes across 2 years (sneaker to satellite or satellite to nesting). We captured 151 ocellated wrasse and tested them on different behavior and cognition assays (scototaxis, shoaling, and two detour-reaching tasks). We found greater divergence across alternative male reproductive phenotypes than differences between the sexes in behavior, problem-solving, and relationships between these traits. Nesting males were significantly less bold than others, while sneaker males were faster problem-solvers and the only phenotype to display a cognitive-behavioral syndrome (significant correlation between boldness and problem-solving speed). Combining these results with prior measurements of sex steroid and stress hormone across males, suggests that nesting and sneaker males represent different coping styles. Our data suggests that transitioning between alternative male phenotypes requires more than changes in physiology (size and ornamentation) and mating tactic (sneaking vs. cooperation), but also involves significant shifts in cognitive-behavioral and coping style plasticity. 

Introduction Evidence of animal personality and behavioral syndromes is widespread across animals, yet the development of these traits remains poorly understood. Previous research has shown that exposure to predators, heterospecifics, and urbanized environments can influence personality and behavioral syndromes. Yet, to date, the influence of early social experiences with conspecifics on the development of adult behavioral traits is far less known. We use swordtail fish ( Xiphophorus nigrensis ), a species with three genetically-determined male mating strategies (courtship display, coercion, or mixed strategy) to assess how different early-life social experiences shape adult behavioral development. Methods We raised female swordtails from birth to adulthood in density-controlled sexual-social treatments that varied in the presence of the type of male mating tactics (coercers only, displayers only, coercers and displayers, and mixed-strategists only). At adulthood, we tested females’ boldness, shyness, aggression, sociality, and activity. Results We found that the number of different mating strategies females were raised with (social complexity) shaped behavioral development more than any individual mating strategy. Females reared in complex environments with two male mating tactics were bolder, less shy, and less aggressive than females reared with a single male mating tactic (either courtship only or coercion only). Complex sexual-social environments produced females with behavioral syndromes (correlations between aggression and activity, shyness and aggression, and social interaction and activity), whereas simple environments did not. Discussion Importantly, the characteristics of these socially-induced behavioral syndromes differ from those driven by predation, but converge on characteristics emerging from animals found in urban environments. Our findings suggest that complexity of the sexual-social environment shapes the development of personality and behavioral syndromes to facilitate social information gathering. Furthermore, our research highlights the previously overlooked influence of sexual selection as a significant contributing factor to diverse behavioral development. 

Abstract Amphibians are ideal for studying visual system evolution because their biphasic (aquatic and terrestrial) life history and ecological diversity expose them to a broad range of visual conditions. Here, we evaluate signatures of selection on visual opsin genes across Neotropical anurans and focus on three diurnal clades that are well-known for the concurrence of conspicuous colors and chemical defense (i.e., aposematism): poison frogs (Dendrobatidae), Harlequin toads (Bufonidae: Atelopus), and pumpkin toadlets (Brachycephalidae: Brachycephalus). We found evidence of positive selection on 44 amino acid sites in LWS, SWS1, SWS2, and RH1 opsin genes, of which one in LWS and two in RH1 have been previously identified as spectral tuning sites in other vertebrates. Given that anurans have mostly nocturnal habits, the patterns of selection revealed new sites that might be important in spectral tuning for frogs, potentially for adaptation to diurnal habits and for color-based intraspecific communication. Furthermore, we provide evidence that SWS2, normally expressed in rod cells in frogs and some salamanders, has likely been lost in the ancestor of Dendrobatidae, suggesting that under low-light levels, dendrobatids have inferior wavelength discrimination compared to other frogs. This loss might follow the origin of diurnal activity in dendrobatids and could have implications for their behavior. Our analyses show that assessments of opsin diversification in across taxa could expand our understanding of the role of sensory system evolution in ecological adaptation.