A STRUCTURAL-EQUATIONS MODEL FOR THE MATING-BEHAVIOR OF BUCKS IN A LEK OF FALLOW DEER

In many studies, the causal factors of male copulatory success in leks cannot be experimentally analysed under natural conditions. Informati on is based on the analysis of correlation and on multiple regression models. However, these methods are often flawed or unsuitable for conc lusive results. By contrast, an explicit model of the breeding behavio ur of male fallow deer (Dama dama L.) has been formulated using struct ural (regression) equations. The model describes with outstanding prec ision the network of short-term determinants of male copulatory succes s. Harem size is identified as the most important indirect cause of ma le copulatory success and, in its turn, it is a function of (i) Iek at tendance, (ii) intensity of herding, (iii) aggressive behaviour toward s other bucks and (iv) courtship. Comparing the results of the structu ral-equations model with those of a partial correlation analysis and o f a multiple regression study, we conclude that the statistical method presented here better describes the complexity of the causal web whic h characterizes leks than other statistical methods commonly used in t hese studies.