Developmental Interaction Between Leucania separate (Lepidoptera: Noctuidae) and Its Braconid Parasitoid, Microplitis mediator (Hymenoptera: Braconidae)

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Abstract
The pattern of host growth after parasitism by the solitary endoparasitoid Microplitis mediator (Haliday) was examined by measuring the weight gain and head capsule size of the host, Leucania separate (Walker). The decrease in the host weight gain was of three patterns, depending on host age at the time of parasitism. The first pattern was an increased rate of weight gain of the host parasitized during the late 1st and early 2nd instar; this rate was linear but lower than that of the unparasitized host. When hosts were parasitized in the late 2nd or the 3rd instar, the second pattern was observed: the host continued normal growth for a few days after parasitoid oviposition, and then growth was markedly inhibited. The third pattern was evidenced by no increase in weight gain when oviposition occurred during the early and late 4th instar. The reduction of the mean size of the host’s head capsule paralleled the decrease in weight gain. The parasitoids appeared to be able to control the host’s weight at some specific level. There was no correlation between the reduction of the host weight gain and the developmental stage of the parasitoid.