Female sensitivity to diet and irradiation treatments underlies sex-mortality differentials in the Mediterranean fruit fly

Large-scale experiments on medflies that were subjected to sterilizing dose s of ionizing radiation (plus intact controls) and maintained on either sug ar-only or full, protein-enriched diets revealed that, whereas the mortalit y trajectories of both intact and irradiated male cohorts maintained on bot h diets are similar, the mortality patterns of females are highly variable. Mean mortality rates at 35 days in male cohorts ranged from 0.2 to 0.3 but in female cohorts ranged from 0.09 to 0.35, depending on treatment. The st udy reports three main influences: (a) qualitative differences exist in the sex-mortality response of medflies subjected to dietary manipulations and irradiation; (b) the female mortality response is linked to increased vulne rability due to the nutritional demands of reproduction; and (c) female sen sitivity to environmental changes underlies the dynamics of the sex-mortali ty differential.