Konrad Lorenz Research Station for Ethology and Institute for Zoology, University of Vienna, Grünau, Austria
The relationship between hormones and behaviour may be investigated in a correlative or in a causal way. To point out the short-time causal effects of testosterone on male behaviour, five greylag males (Anser anser), belonging to different social classes, were implanted with testosterone, and five males were used as controls, implanted with empty silastic tubes. Observations were performed daily for seven weeks, including a control week before implantation, by using "The Observer" program and a Psion Organiser LZ64 handheld computer. Data were collected as continuous sampling for the ten ganders and their partners. Observed behaviours included vigilance positions, aggressive events and courtship behaviours. Fecal samples were collected once per day and analysed by sensitive enzyme-immuno-assays. Behavioural differences within one individual and among individuals before and after implantation will be discussed.
Funded by University of Milano (Milano, Italy) and FWF-Project P10483-BIO.