Persistent courtship reduces male and female longevity in captive tsetse flies <i>Glossina morsitans morsitans</i> Westwood (Diptera: Glossinidae)

Where males can increase their mating success by harassing females until they accept copulation, harassing tactics can be expected to evolve to a point where they have costs to the longevity of both sexes. By experimentally manipulating the sex ratio in captive groups of tsetse flies Glossina morsitans morsitans, we demonstrated that the longevity of females declines where sex ratios are biased toward males, while the longevity of males declines where the sex ratio is biased toward females. Neither irradiation of males nor prevention of copulation by blocking or damaging the external male genitalia increased the longevity of females caged with them, suggesting that female longevity was reduced by the physical aspects of male harassment rather than by components of the ejaculate