Sexual conflict and the evolution of male elaboration in the water strider genus Rheumatobates (Heteroptera: gerridae)

grantor: University of TorontoNew views of animal mating systems are increasingly focusing on the role of sexual conflict as a preeminent force in the evolutionary divergence of behaviours and morphology. In this thesis, I focus on a macroevolutionary approach to the morphological diversification in the water strider genus Rheumatobates. This genus is distinguished by a remarkable diversity of bizarre modifications of male structures, thought to evolve under sexual conflict. Observation indicates that the structures are used to overcome females, and a pair of experiments demonstrate these advantages are balanced by developmental costs. I then reconstruct the first phylogeny of the genus using a new data set of 108 morphological characters. The phylogeny reveals multiple evolutionary transitions in most modifications of males traits. Although there appears to be repeated functional convergence, it is underlain by remarkable morphological diversification. These results support the theoretical predictions of an arms race fueled by sexual conflict.M.Sc