MONOGAMIX

Most studies of mate choice in monogamous species have focused on the influence of absolute criteria (either phenotypic or genetic). However, it is now largely admitted that relative criteria (phenotypic or genetic compatibility) might be just as important. In particular the relative importance of each type of criterion is still unclear, as well as the possibility for animals to combine both types of criterion in their decision rules. We propose to investigate this question using a two-fold approach. First, we propose to develop two types of mathematical models. The first one is a game-theoretical approach, to evaluate to what extent the optimal decision regarding keeping the same mate or switching mates between reproductive attempts, depends on the extent of inter-individual variation in intrinsic quality, and on the degree of variability in compatibility between potential mates. The second model is an individual-based model, through which we will examine the influence of the extent of inter-individual variation in intrinsic quality and of the degree of variability in compatibility between potential mates, on the decision rules used by animals to select a new mate. Two rules will be considered: the "threshold decision rule" and the "best-of-n" rule. Empirical studies will be conducted on three monogamous species with contrasted life-history traits: the endoparasite Schistosoma mansoni, the Zenaida dove, Zenaida aurita, and the Alpine marmot, Marmota marmota. A certain number of research questions will be addressed in all three species: 1) Is there any difference between sexes in propensity to switch mates? 2) Does genetic dissimilarity influence patterns of mate-switching? 3) What is the relative influence of absolute versus relative preference in decision to switch mates? Some additional questions will however be specific to only one model. The project brings together three research teams with complimentary skills in behavioural ecology, genetics and mathematical modelling. Besides, each team is familiar with one of the three biological models. The expected results should contribute to a better undertsanding of the factors influencing mate choice in monogamous species and of the consequences of such choice in terms of genetic diversity among populations.