The Thermal Adaptability of Sclerodermus guani Xiao et Wu (Hymenoptera: Bethylidae), an Important Parasitoid of Long-Horned Beetles in China

<i>Sclerodermus guani</i> is the most extensively studied and widely used parasitoid wasp for controlling forest trunk-boring pests in China, with temperature being a key environmental factor affecting its development and reproduction. Against the backdrop of global climate change, the frequency of heat stress on parasitoid wasps is increasing. Therefore, studying their adaptability to heat stress is of great significance for breeding heat-tolerant strains. The findings of such research may help improve efficiency in rearing this wasp and provide guidance for its use in pest control. This study investigated the thermal adaptability of the wasp at temperatures ranging from 21 to 33 °C. The results showed that temperature significantly affected its parasitism capacity and behavior. As temperature increased, female wasps searched for and stung hosts more actively, and their pre-oviposition period decreased, as well as their developmental duration. The reproductive fitness of the wasp also varied significantly with temperature, with the most favorable temperatures being 27 °C and 30 °C. Both low and high temperatures were detrimental to its reproduction, and the difference in the number of female offspring was significant. The experimental results indicate that <i>S. guani</i> has higher reproductive fitness at 27-30 °C. Therefore, it is recommended that this parasitoid wasp be reared indoors at 27-30 °C and released for pest control in forests when the temperature is above 24 °C.