Impact of Short-Term High Temperature on Microplitis manilae (Hymenoptera: Braconidae) Survival, Fecundity and...

With global warming and an increase in the frequency of extreme heat events, uncertainty has arisen about the survival and fertility of insects that are enemies in the wild. In this study, we employed the generalized linear model (GLMs) for analysis to elucidate the effects of short-term high temperatures on the survival, fecundity, and progeny of Microplitis manilae Ashmead (Hymenoptera: Braconidae), a key parasitic natural enemy of early instar larvae of Spodoptera litura Fabricius (Lepidoptera: Noctuidae). We conducted laboratory tests to assess the survival and lifespan of M. manilae adults at high temperatures of 35°C, 37°C, and 39°C, with exposure durations of 1, 3, 5, 7, and 9 h. We also evaluated the fecundity and longevity of the F₁ generation adults, as well as the development of the F₂ generation, following exposure at the same high temperatures for 5 h. The results indicated that M. manilae adult stages were significantly affected by elevated temperatures across different exposure durations, particularly when the duration exceeded 5 h. Under different high-temperature exposures for 5 h, fecundity and longevity were significantly suppressed in the F₁ generation, along with impaired growth and development in the F₂ generation when the temperature exceeded 39°C. This study reveals the effects of short-term high-temperature stress on the survival, reproduction, and progeny development of M. manilae. It provides a theoretical basis for understanding the biological evolution mechanism of M. manilae in response to thermal stress and the biological control of pests by M. manilae in high-temperature seasons.