The link between animal personality and habitat selection in males of the Neotropical poison frog Allobates femoralis.

Environmental variation plays a key role in the evolution and maintenance of animal personality. Individuals with different personality types might exhibit different habitat preferences. Alternatively, variation in individual behaviour across space could arise as a plastic adaptation to distinct habitats. Our study aims to investigate if habitat choice is influenced by an individual's personality. We assessed individual levels of activity, boldness, and exploration in male poison frogs, and performed a habitat choice test under controlled laboratory conditions. Individuals were consistent in their behaviours, but all tested frogs chose the complex over the simple habitat. Individuals that were characterized as bold and very explorative also showed more movements between the two different habitats in the choice test. These results indicate that personality measured in a highly standardized artificial setup, such as a novel environment test, indeed can reflect boldness and exploration related behaviours measured in a more naturalistic setup.

Regardless of personality, males show similar levels of plasticity in territory defense in a Neotropical poison frog.

Animal personality traits are sometimes linked to an individual's degree of plasticity, with certain personality types being more plastic than others. In territorial species, consistently high levels of aggression might increase the risk of harmful fights, while consistently low aggression might lead to the loss of a territory. Consequently, reacting plastically with an appropriate territorial response should be beneficial to avoid these risks. An integrative investigation of both personality traits and plasticity can help us better understand the dynamics of aggressive interactions during male-male competition. Here, we used a free-ranging Neotropical poison frog population to investigate the role of plasticity in male territorial aggression towards intruders. We conducted repeated standardized territorial intrusion experiments mimicking frogs of different body sizes via playback calls with different peak frequencies. We found individual repeatability for the latency to reach and approach a simulated intruder and observed that both aggressive and less aggressive males decreased their level of aggression towards big intruders. However, our results do not support a correlation between personality and plasticity in the context of male territory defense during the breeding season. We discuss how such a correlation between personality and plasticity might be conditional on the costs and benefits across contexts.

Behavioural consistency across metamorphosis in a neotropical poison frog.

Animals often show consistency in their behavioural repertoire across time and/or contexts that differs from other individuals of the same population, i.e. animal personality. We currently have quite an incomplete understanding of the factors that lead to behavioural traits remaining stable - or becoming decoupled - over an animal's lifetime. In this study, we investigated the role of metamorphosis in the development of animal personality in a Neotropical poison frog, a species that undergoes drastic morphological and ecological changes during its development. We used lab-reared individuals of the brilliant-thighed poison frog Allobates femoralis to assess if consistent individual differences are already present at the tadpole stage, and if these differences are maintained throughout metamorphosis. We found evidence for two personality traits, exploration and boldness, already present in A. femoralis tadpoles. Despite the drastic changes in morphology, physiology, and habitat in the transition from tadpoles to metamorphs, personality traits persisted throughout metamorphosis, suggesting a physiological and/or genetic basis for the measured behavioural traits. We also found that exploration and boldness related behaviours were correlated with growth speed. Very bold and explorative individuals took fewer days until metamorphosis compared to very shy and non-explorative ones, which is in line with the concept of a Pace-of-Life Syndrome. These findings provide important insights into the proximate mechanisms that generate personality in species with complex life cycles.

Mate choice in a promiscuous poison frog.

In many animal species, members of one sex, most often females, exhibit a strong preference for mating partners with particular traits or resources. However, when females sequentially mate with multiple partners, strategies underlying female choice are not very well understood. Particularly, little is known if under such sequential polyandry females mate truly randomly, or if they actively try to spread mating events across multiple partners. In the present study, we used the highly promiscuous poison frog Allobates femoralis to investigate whether promiscuity could result from a preference for novel mates. Furthermore, we examined the importance of call characteristics for mate choice. We conducted mate choice experiments in a laboratory setup, by presenting females with recent mating partners or novel males. We recorded call characteristics of both males and the time females spent close to each male. In our trials, females preferred previous mating partners over novel males and also males with shorter advertisement calls. Results from previous studies on A. femoralis suggest that females in our trials recognized previous partners based on individual call characteristics. While mating decisions in the wild and in the laboratory might differ, our study provides first evidence for female mate choice in a poison frog with sequential polyandry.

Exploring links between personality traits and their social and non-social environments in wild poison frogs.

An animal's behavioral phenotype comprises several traits, which are hierarchically structured in functional units. This is manifested in measured behaviors often being correlated, partly reflecting the need of a coordinated functional response. Unfortunately, we still have limited understanding whether consistent differences in animal behaviors are due to underlying physiological constraints or a result of plastic adaptation to their current environment. Therefore, characterizing the spatial distribution of behaviors can provide important insights into causes and consequences of behavioral variation. In the present study, we quantified behaviors in a wild, free-ranging population of the Neotropical frog Allobates femoralis. We investigated how these behaviors were linked to the frogs' natural and social environment and quantified the extent to which these behaviors consistently differed among individuals (i.e., animal personality). We assessed levels of aggressiveness, exploration, and boldness by measuring several underlying behaviors expressed in a set of experimental assays, and found evidence for consistent among-individual differences along these axes. Contrary to our expectation, there was no relationship between individual behaviors and their natural environment, but we found a plastic response of males to changes in female density, which might reflect how individuals cope with their socio-ecological environment. Significance statement: How are behavioral phenotypes distributed across space? Here, we studied an entire free-ranging population of poison frogs, and investigated if the personality traits aggressiveness, exploration, and boldness are linked to the frogs' natural or social environment. We found that behavioral traits were non-randomly distributed across the population, suggesting that the spatial arrangement of behavioral traits reflects how individuals cope with their complex natural and social environment.