Competition defined as an interaction between individuals due to a shared requirement for a common resource. In this study, the experimental unit consisted one five instar larva of Ephestia kuehniella bearing 12 Habrobracon hebetor eggs, which was replicated 25 times. From 25 replicates, in three units only female wasps and from two units only males were emerged. The remained units included male and female wasps together. Male longevity at only male included units was 12.75 ±1.5 days, while in two sexed units it was reduced to 9.4±0.8 days might be assigned to the competitive pressure of females due to their larger body size and more nutritional needs.