none The authors conducted two experiments on the oviposition strategy of the gregarious parasitoid, Apanteles glomeratus. First, the relationship between the egg number per host (N) and the reproductive success of the eggs in terms of dry weight of parasitoid offspring was estimated. There are certain limitations in the egg supply and life span of a wasp, hence the number of hosts in which she can oviposit in her lifetime is also limited. When the density of hosts is high enough to deposit all her eggs, it is better to maximize the reproductive success gained from each egg. The result of the second experiment agreed with this prediction; when the wasps were offered the hosts at long intervals, they laid 35-40 eggs in each host, while when offered the hosts with high frequency, they reduced the egg number per host to ca. 20.