Animal personality and sexual selection

Naturalists and pet owners have long intuitively recognized that individual animals show personality. Only within the last decade the topic animal personalities have received considerable attention in the scientific community, after consistent individual differences in behaviour have been documented across a wide range of taxa, including species with very simple nervous systems, such as sea anemones and hermit crabs. At the same time, these behavioural differences are expected to have dramatic effects on an individuals fate - in terms of produced offspring and own chances of survival. Previous research has mainly focused on the response of single individuals to changes in their environment or to specific test conditions. However, most behaviour in the context of reproduction and survival is expressed in a social context, with two or more individuals involved. Therefore, in our proposed project Show-off or shy boy? The interplay between animal personality and sexual selection we will investigate how personality differences are reflected in behaviours such as male-male competition and space use, mate choice, and parental care; and how these differences ultimately affect an individuals survival and reproductive performance. The project will focus on the model species Allobates femoralis, a Neotropical poison frog with a prolonged breeding season, pronounced male territoriality, and male parental care. The study will be carried out in an experimental island population in French Guiana. The ability to monitor, assay, and track an entire animal population in its natural habitat in an island setup over several generations makes this project exceptional. All individuals are genetically sampled and their position in a consistent pedigree is known. By identifying respective costs and benefits of specific personality profiles, the proposed project will help us to better understand how behavioural variation can persist over evolutionary time.

Naturalists and pet owners have long intuitively recognized that individual animals show 'personality'. Only within the last decade the topic 'animal personalities' have received considerable attention in the scientific community, after consistent individual differences in behaviour have been documented across a wide range of taxa, including species with very simple nervous systems, such as sea anemones and hermit crabs. In the project "Animal personality and sexual selection" we investigated why there is individuality in behaviour in poison frogs. We tried to address this question from two angles. On one hand, we asked why and how these individual differences arise? On the other hand, we investigated why these differences are maintained in animal populations over time. The project focused on the model species Allobates femoralis, a Neotropical poison frog with a prolonged breeding season, pronounced territoriality, and parental care. The study was mainly carried out in an experimental population in French Guiana, but some additional experiments were also conducted in our captive colony. By monitoring and assaying the natural population over the course of 4 years, we investigated how personality differences regarding aggression, boldness, and exploration impact on male-male competition and space use, mate choice, and parental care; and how these differences ultimately affect an individual's survival and reproductive performance. We found that male and female poison frogs display several personality traits that, combined with behavioural plasticity, helps them cope with variation in their natural and social environment. We also show that personality traits can have different - even opposite - effects on the various components of reproductive success - highlighting that there is no "best behavioural type" across several different social contexts. Furthermore, we investigated the role of hormones on behavioural variation and found a link between testosterone and the personality trait 'exploration'. We also found evidence for the existence of personality already in tadpoles, and that these behavioural types remain consistent over metamorphosis. All these findings contribute to our knowledge about evolutionary processes that create and maintain behavioural diversity in animals.