Sexual conflict is expected to be widespread in nature as males and females do not fully share their evolutionary interests. In waterfowl sexual conflict over forced copulations has led to the antagonistic evolution of genital traits that result from an evolutionary arms race as males try to bypass female choice. Females have regained control of reproduction in this system where males overpower them by force. Males have evolved a unique erection mechanism, but females can limit the success of unwanted copulations via the evolution of complex vaginas. Male-male competition appears to be the primary selective agent acting on penis size, with antagonistic coevolution further increasing complex morphology in the system.

Lecture sponsored by the Norman E. Hartweg fund