The purpose of this research is to elucidate the relationship of male parental care and sexual selection in two species of midwife toads (alytes obstetricians and A. cisternasii, Anura, Discoglossidae). Evidence for partial or total sex role reversal will be sought through the quantification of intrasexual competition for mates and mate choice selectivity. The project will involve 1) Monitoring of natural populations of marked individuals. 2) Laboratory analysis of caloric content to determine the relative energetic cost of reproduction in each sex. 3) Laboratory and field observations to determine the intensity of intrasexual competition for mates in both sexes. 4) Laboratory and field experiments with synthesized calls to determine selectivity based on acoustical communication. The comparison of the two species will constitute a unique test of the hypothesis which states that relative parental investment determines sex roles and hence determines which sex will be more subject to sexual selection. The results obtained will permit the discrimination between the effect of male parental investment on sexual selection and on its outcome.
