LABORATORY BIOLOGY OF A UNIPARENTAL STRAIN OF METEORUS-PULCHRICORNIS (HYMENOPTERA, BRACONIDAE), AN EXOTIC LARVAL PARASITE OF THE GYPSY-MOTH (LEPIDOPTERA, LYMANTRIIDAE)

The ovipositional response of a uniparental Korean strain of the parasite Meteorus pulchricornis (Wesmael) offered first to third instars of the gypsy moth, Lymantria dispar (L.), indicated that parasitization was significantly higher in hosts offered as second instars. Over their lifetimes, which averaged 44 d, females of M. pulchricornis, offered 15 second instars per day deposited an average of 268 eggs and attacked an average of 194 hosts. Rates of parasitization and superparasitization averaged 32 and 31%, respectively. At 24-degrees-C, development from egg to adult required 16-32 d. The uniparental Korean strain of M. pulchricornis differed from the biparental European strain by its thelytokous mode of reproduction and by having a reduced tendency to attack third instars of gypsy moth, the preferred host for the European strain. Production of F1 males by a few individual females in quarantine suggested that biparental strains of M. pulchricornis are present in the Far East. Attempts to hybridize the uniparental Korean strain with the biparental European strain were unsuccessful.