Meeting Abstract

85.6  Tuesday, Jan. 6  Sexual selection on body size and secondary sexual characters in two closely related, sympatric chameleon species in Madagascar KARSTEN, K.B.*; ANDRIAMANDIMBIARISOA, L.N.; FOX, S.F.; RAXWORTHY, C.J.; Oklahoma State University; University of Antananarivo; Oklahoma State University; American Museum of Natural History k.karsten@tcu.edu

In polygynous mating systems, sexual selection can drive the evolution of male characters beneficial to winning fights (intrasexual selection), for improving the mating success of males through mate choice (intersexual selection), or both. However, it may be difficult to disentangle the relative contributions of intra- and intersexual selection on multiple traits that may be of dual utility. We used field arena trials to determine which morphological traits best explained male fighting ability and male mating success in two species of chameleons in Madagascar, Furcifer labordi and F. verrucosus. In F. labordi, male fighting success was best predicted by body size and cranial casque height and male mating success was best predicted by body size and width of the rostral appendage. In F. verrucosus, we found strong intrasexual selection for increased male body size and fewer counted dorsal cones, a trait that may correspond to age and experience. Although there appears to be little mate choice in this species, male mating success with receptive females is highly variable. Fewer counted dorsal cones and larger size-corrected casque height best explained male mating success; traits that may again indicate age or experience. Although difficult to determine the relative contributions of intra- and intersexual selection on traits with dual benefits (both fighting and mate choice), we documented both types of selection on body size and secondary sexual characters in these two chameleon species.