Impairment affects mating costs and behavior in male medflies (Diptera:Tephritidae)

Male tephritid flies experience progressive and persistent levels of damage as a cost associated with mating. Damage acquired during mating leads to impairment, which affects an individual’s survival and behavior. In this study, we tested how artificial impairment and mating costs interact to influence longevity and behavior in male medflies (Ceratitis capitata (Wiedemann)). Treatment flies were impaired through the amputation of tarsal segments 2-5 from the front right leg, while intact males served as the control. Treatment and control flies were housed either solitarily or paired with a virgin female, and daily survival was recorded until death. Behavioral effects of impairment were quantified through hourly observation of courtship and copulation frequencies during an 8 h period. The cost of female access in the absence of amputation was a decrease in lifespan. Amputation of solitarily housed (virgin) males also caused a reduction in longevity. The combination of female access and artificial impairment reduced survival for individuals over 20 days old, but did not decrease life expectancy more than that of males with female access alone. The impaired males had less success in copulating than intact males, but no differences were observed in the rates of sexual signaling. Impairment did not reduce the males' propensity to mate but affected the willingness of females to allow copulation; therefore, minor impairment lowers the mating fitness of males while having a negligible effect on longevity.