SFB-TRR 212

Social niche conformance and social niche transition during adolescence and beyond: effects on biobehavioural profiles and fitness

For group-living animals, members of the same species constitute a major part of their environment. This social environment can vary significantly. For example, it can consist of high or low individual numbers. The interaction of an animal with its social environment results in individualised social niches, which are also distinctly affected by the individuals' internal state. In order to maximize their Darwinian fitness animals have to conform to their environments. For this purpose, mechanisms for an adaptive shaping of behavioural phenotypes have evolved during early phases of life in numerous species throughout the animal kingdom. Whether or not such an adaptive shaping can also occur later in life is largely unknown.

Using guinea pigs as a model system, this project asks for the first time, whether in a higher vertebrate social niche conformance does also occur during adolescence and beyond. We will study both sexes and we will, in addition, investigate the role of the females' internal states for an adaptive shaping of their biobehavioural profile. Thus, the overall aim of this project is to elucidate the process of social niche conformance in males and females during later phases of life. Furthermore, we will analyse whether individualised social niche transitions in adulthood result in adaptive shaping of their biobehavioural profiles.

Since cortisol reactivity proves more and more to be a key element of physiological adaptation in vertebrates, we will not only focus on the behaviour and reproductive output, but also on this neuroendocrine parameter as an important underlying mechanism. More specifically, in males we will compare individuals living in three different individualised social niches during adolescence and beyond: dominant and subdominant males at high individual number situations that compete intensively for reproductive success as well as males living at low individual numbers with unrestricted access to mating partners. Regarding females, the biobehavioural profiles of pregnant and non-pregnant as well as of dominant and subdominant animals during adolescence and beyond will be assessed. In addition, in both sexes niche transitions - e.g., from low to high ranking positions and vice versa - will be experimentally induced and it will be analysed whether or not the animals respond in an adaptive way. In summary, this project will contribute substantially to the question whether animals do conform to social environments in a sex-specific and an adaptive way during adolescence and beyond.