none Outcomes from intraspecific competition for the arrhenotokous parasitoid Microplitis croceipes (Cresson) were determined using mated and unmated females. The survival rate of progeny of a superparasitizing female is equal to that of the female ovipositing first when the two ovipositions occur on the same day. However, the survival rate of progeny of a superparasitizing female decreases with increased time between initial oviposition and superparasitization. There was no apparent intrinsic superiority of one sex of parasitoid larvae over the other in larval-larval competition. Protandry in M. croceipes is a result of accelerated pupal development of males, not accelerated larval development.