Rearing of Ostrinia palustralis (Lepidoptera: Crambidae) larvae with a switchover of two kinds of artificial diets

Abstract

A method was established to rear the entire larval stage of Ostrinia palustralis, an oligophagous species that feeds on dock plants Rumex spp., on artificial diets. Silkmate L4M (an artificial diet for the " polyphagous" silkworm mutants) supplemented with 20% R. japonicus dried leaf powder was initially provided to the neonate larvae, and the diet was switched to Silkmate 2M (a standard diet for silkworms) 14 days post-inoculation. These diets supported larval growth with a pupation rate of about 70%. This rate was comparable to that for conventional rearing using fresh host plant leaves. Although the larval period was significantly extended as compared with the conventional rearing, no difference in the pupal weight was found between the two groups. The number of eggs laid by the resultant adult females and the hatchability of the eggs were also comparable. Utilization of the two kinds of artificial diets enabled rearing of this species throughout the year with much reduced labor.