Interaction between a nucleopolyhedrovirus and the braconid parasitoid Meteorus pulchricornis (Hymenoptera: Braconidae) in the larvae of Spodoptera litura (Lepidoptera: Noctuidae)

Abstract

We investigated the survival and development of the braconid parasitoid Meteorus pulchricornis in nucleopolyhedrovirus (NPV)-infected Spodoptera litura larvae. The first and second molting stages of the larvae were parasitized by M. pulchricornis and were exposed to a 95% lethal concentration (LC95) and 10X the LC95 of S. litura NPV (SpltNPV) on the first, third, and fifth day post-parasitization (dpp). Infection of the larvae with SpltNPV was deleterious to the survival and development of M. pulchricornis. The survival of M. pulchricornis in SpltNPV-infected S. litura larvae was dependent on the interval between parasitization and viral infection, as well as on the inoculation dose of SpltNPV; few parasitoid larvae emerged from infected hosts when host larvae were exposed to 10X the LC95 of SpltNPV on 1 and 3 dpp. The fecundity of M. pulchricornis that emerged from SpltNPV-infected hosts was not affected, and these parasitoids did not transmit the virus to other hosts. The number of eggs laid by M. pulchricornis females was not significantly different between the SpltNPV-infected and non-infected larvae during the first 4 d post-infection (dpi). On the other hand, at 5 dpi, M. pulchricornis females laid significantly more eggs in non-infected larvae than in SpltNPV-infected larvae.