Effect of the number of parasitoid (Apanteles kariyai) eggs [Hym.: Braconidae] on the growth of host (Leucania separata) larvae [Lep.: Noctuidae]

The developmental interactions between a gregarious endoparasitoid,Apanteles kariyai Watanabe and its host,Leucania separata Walker, were investigated. The parasitoid laid more eggs in older hosts. Host size increased gradiently as the instar advanced, but the number of eggs laid per host did not increase accordingly. The net weight of the host was correlated positively with the number of eggs laid and with the total weight of parasitoids, especially in cases of parasitization at 3rd (5th-instar type), 4th and early 6th instar where the correlation was significant at 1% level. It follows therefore that the more parasitoids there are relative to their host size, the more they contribute to make the host size larger.