Impact of heat waves on egg survival and biological performance across life stages in the Asian corn borer

Abstract

AbstractOne of the many extreme events as a result of climate change is the frequent appearance of extraordinarily daily high temperatures that can directly drive an insect's adaptive response. Insects have complex life cycles that may uncouple temperature's effects in one stage from the physiology in the next. In this study we focused on the Asian corn borer (ACB), Ostrinia furnacalis (Guenée) (Lepidoptera: Crambidae), one of the most important pests of maize (corn) in Asia, investigated the consequences of eggs exposed to ecologically relevant heat shock regimes, simulating heat waves at extreme high temperature. This consisted of five 90‐min heat treatments separated by two degrees that ranged from 37 to 45°C for three consecutive days compared to a constant temperature of 25°C. Temperature that triggered mortality was between 39 and 41°C. Egg hatching significantly declined when temperature was 41°C or higher. There was no egg hatching at 45°C. Developmental times were significantly prolonged and the larval growth rate became slower in treatments of 41 and 43°C. There were no significant differences in pupal mass, fecundity, and sex ratio among treatments. Life table parameters showed significant adverse effects at treatments of 41 and 43°C. Depending on the fitness response of the ACB, environmental heat waves can be classified into three categories based on temperature criteria, i.e., adaptable (35–39°C), critical (39–45°C), and fatal (≥45°C). The findings of the present study will serve as an important reference for forecasting the population dynamics of the ACB.