Impact of Different Temperatures on Activity of the Pest Monolepta hieroglyphica Motschulsky (Coleoptera: Chrysomelidae).

Abstract

Monolepta hieroglyphica (Motschulsky) (Coleoptera: Chrysomelidae) is widely distributed in China and is polyphorous, being a major pest to cash crops, such as corn, cotton, and millet. Given the increasing severity of the greenhouse effect in recent years, we aimed to investigate the adaptability of M. hieroglyphica adults to varying temperatures. In this study, we assessed the survival, longevity, fecundity, feeding capacity, and antioxidant capacity of leaf beetle adults under laboratory conditions at 25-34 °C. Elevated temperatures (i.e., 31 and 34 °C) had (negative) impacts on M. hieroglyphica adults' survival and reproduction. Similarly, the temperature negatively affected the feeding capacity of M. hieroglyphica adults, with the impact becoming more pronounced as the temperature increased. Under the same treatment time, the SOD and CAT activity levels increased with the increase in treatment temperature. The GST activity levels showed a decreasing trend. The POD activity showed a biphasic response to increasing temperatures, first decreasing and then increasing. The above indicates that different antioxidant enzymes of M. hieroglyphica adults have different levels of sensitivity to high temperatures. In the laboratory, our work analyzes the response of M. hieroglyphica adults to temperature from ecological and physiological research perspectives and provides strategies for strengthening its subsequent integrated pest management (IPM) under conditions of global warming or extreme weather events.