Effects of Host Diet on the Orientation, Development, and Subsequent Generations of the Gypsy Moth (Lepidoptera: Lymantriidae) Egg Parasitoid Ooencyrtus kuvanae (Hymenoptera: Encyrtidae)

Abstract

Female Ooencyrtus kuvanae (Howard) were attracted to odors from gypsy moth, Lymantria dispar (L.), egg masses in a 4-way olfactometer. Responses to egg mass odors varied with the difference of larval diet of the host. The number of gypsy moth generations on a particular larval diet also appeared to affect parasitoid orientation to the resulting egg masses. The plant species on which gypsy moth larvae fed affected characteristics of both the egg masses and the emerging wasps. Gypsy moth egg masses derived from plant-fed larvae had larger, but fewer, eggs than those derived from larvae fed artificial diet. The effects of host larval food on egg parasitoid emergence appeared in the 2nd generation, apparently because wasp developmental substrate affected their fecundity. O. kuvanae that developed in eggs derived from oak-fed gypsy moths produced more offspring than those that developed in eggs derived from tamarack-fed gypsy moths, regardless of subsequent ovipositional substrate. The offspring sex ratio was influenced by the ovipositional and parental substrates. The proportion of females was highest in larval treatments and egg mass sections that yielded the largest eggs. O. kuvanae generally parasitized more eggs in the section of the egg mass that was laid first by the gypsy moth.