Erratum to: Exposure to mild temperatures decreases overwintering larval survival and post-diapause reproductive potential in the rice stem borer Chilo suppressalis

Abstract

The rice stem borer, Chilo suppressalis Walker, overwinters as larvae that undergo facultative diapause in response to short day lengths. This study tested the hypothesis that exposure to warm temperature reduces the survivorship of overwintering larvae, thereby eventually decreasing the outbreak in the following year. We exposed overwintering larvae to various temperature treatments of 1, 5 and 10 °C and natural conditions with a daily mean temperature of 9.3 °C for 5–6 months. As C. suppressalis undergoes three complete generations and a partial fourth generation each year, we systematically compared the survival rates and the body weights of overwintering larvae, the dynamics of diapause termination (i.e., pupation rate), and the post-diapause reproductive potential, as indicated by pupal weight and female fecundity among the treatments. In all treatments, we observed a gradual decline in the survival rate of overwintering larvae, starting in October for the third generation and in November for the fourth generation and continuing until the following May. Temperature treatments significantly affected the body weights of overwintering larvae. Simulated warmer winter temperatures also resulted in similar declines in pupation rate, pupal weight and post-diapause reproductive potential. It was the relatively lower temperatures of 1 and 5 °C, rather than the warm temperature of 10 °C, that was propitious to the survival of overwintering larvae and increased post-diapause reproduction potential in the following year. Therefore, exposure to warm temperatures is detrimental to overwintering populations of C.suppressalis, which provides useful information for monitoring their population dynamics in practice. Warmer temperatures are generally considered favorable for increasing the overwintering survival of insects in some climatic areas; however, this is unlikely to be a universal effect. The influence of temperatures during overwintering upon survival and post-diapause reproductive potential in C. suppressalis was tested; the survivorship was actually lower at the higher temperature. The results suggest that mild warm temperatures near the threshold temperature for post-diapause development decreased the survival of overwintering larvae and the post-diapause reproductive potential in the rice stem borer C. suppressalis.