Sclerodermus guani 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 S. guani 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.

Sclerodermus guani Xiao et Wu, Sclerodermus sichuanensis Xiao, Sclerodermus pupariae Yang et Yao, and Sclerodermus alternatusi Yang are four species of Sclerodermus that have been found in China on longhorn or buprestid beetle hosts. These parasitoids are of great importance to forest management because they control certain forest pests. Knowledge of their developmental differences is important for maximizing their use in bio-control programs, yet little about them is known. This study compared their number of offspring and developmental biology. There were significant differences in the four parasitoids’ egg, larval, pupal, and total developmental stages. The F₂ male offspring of each parasitoid emerged approximately one day ahead of the female. Additionally, there were differences in the number of F₂ male and female offspring, as well as in the sex percentage, among the four parasitoids. Compared to the other three wasps, S. alternatusi had a significantly lower F₂ female percentage of 67.07%, which was notably less than that of the other wasps (over 90%). The total F₂ offspring number and F₂ female offspring number of S. guani were the greatest. Sclerodermus alteratusi produced a larger percentage of winged females (5.66%) compared to S. pupariae (3.98%), and no winged females developed from S. guani or S. sichuanensis. Almost all individuals survived the 30-day experiment, the survival rate decreased to about half after 120 days at 12 °C, and there was no difference between the species. The biological differences between the four wasp species analyzed in this study will help improve the effectiveness of mass-rearing them for the biological control of forest pests.