Parasitization and Life History Parameters of Exorista japonica (Diptera: Tachinidae) Using the Common Armyworm, Pseudaletia separata (Lepidoptera: Noctuidae) as a Host

The biology of the tachinid fly, Exorista TOWNSEND, a natural enemy of many lepidopterous larvae, was studied under laboratory conditions (25°C, 60% RH and 16L-8D) in order to establish an efficient rearing method. The number of eggs on the host and the relationship between egg period and duration to the next moulting of host were primary influences on the success of parasitization. When 1, 2 and 3 eggs were laid on a day 1 lastinstar larval host, Pseudaletia separata WALKER, the percentages of parasitism were 64.6, 88, 9 and 100.0%, respectively. The frequency of oviposition was negatively correlated with longevity of female adults. The mean longevity of females provided with hosts every day (34.2 days) was significantly shorter than that of females provided with hosts once every 4-5 days (56.4 days). Rearing about 7 generations of the parasitoid would provide an entire year's supply of fertilized eggs for experimental use in the laboratory.