Cooperative breeding
In the cooperatively breeding Lake Tanganyika cichlid Neolamprologus
pulcher, I investigated two main decisions of helpers: why they stay in
the territory instead of leaving to reproduce on their own, and why they
help raising offspring of others. I could show experimentally that ecological
constraints, particularly the lack of vacant sites suitable for independent
breeding prevent helpers to disperse and breed on their own. Further more
I found evidence supporting the 'pay-to-stay hypothesis' which
proposes that, in order to be allowed to stay in the dominants territory,
subordinates pay a 'rent' by helping the dominants to raise their offspring.
Field observations and experiments suggest that helpers may strategically
disperse between groups which may lead to a biological market situation
were helpers trade for instance their ability to help for access to a high
quality territory.
Animal cognition
The differences in cognitive abilities between species might
be strongly linked to the challenges animals encounter in their
natural and social environment. Cleaner fish (Labroides dimidiatus)
rely completely on the food they obtain from the client fish that visit
cleaner stations to get cleaned from their parasites. However, besides
removing the parasites from their clients tissue cleaners appear to
prefer to feed on their clients' mucus which they obtain when biting
the client fish. This results in a conflict of interests between cleaners
and their clients with regards to goods and services exchanged in
interactions. I use a comparative approach to test the cognitive
capabilities of different species of wrasses in the context of co-
operation from an ecological perspective.
Primate behavioural ecology
In the Tai National Park in Ivory Coast I studied the link between feeding
ecology and the social organisation in the terrestrial sooty mangabeys
(Cercocebus torquatus atys). The results of this study suggest that
mangabeys react to changes in the distribution of food in time and space
by adjusting their group size.
