A cost of reproduction in Drosophila melanogaster: Stress susceptibility

Little is known about physiological mechanisms that underlie the cost of re production. We tested the hypothesis that stress susceptibility is a cost o f reproduction. In one test of our hypothesis, Drosophila melanogaster fema les were exposed to a juvenile hormone analog (methoprene) to stimulate egg production followed by stress assays. A sterile stock of D. melanogaster w as employed as a control for reproduction. Exposure of fertile females to m ethoprene resulted in an increase in female reproduction and increased susc eptibility to oxidative stress and starvation (compared to solvent controls ). Sterile females did not exhibit a decrease in stress resistance. Mating also stimulated egg production. As a second test of our hypothesis, mated f emales were compared to virgin females. Mated fertile females were relative ly susceptible to oxidative stress. but this relationship was not evident w hen mated and virgin sterile females were compared. The results of the pres ent study support the hypothesis that stress susceptibility is a cost of re production.