Comparing the Developmental Biology and Brood Size of Four Sclerodermus Species (Hymenoptera: Bethylidae)

<i>Sclerodermus guani</i> Xiao et Wu, <i>Sclerodermus sichuanensis</i> Xiao, <i>Sclerodermus pupariae</i> Yang et Yao, and <i>Sclerodermus alternatusi</i> Yang are four species of <i>Sclerodermus</i> 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 <i>F</i>₂ male offspring of each parasitoid emerged approximately one day ahead of the female. Additionally, there were differences in the number of <i>F</i>₂ male and female offspring, as well as in the sex percentage, among the four parasitoids. Compared to the other three wasps, <i>S. alternatusi</i> had a significantly lower <i>F</i>₂ female percentage of 67.07%, which was notably less than that of the other wasps (over 90%). The total <i>F</i>₂ offspring number and <i>F</i>₂ female offspring number of <i>S. guani</i> were the greatest. <i>Sclerodermus alteratusi</i> produced a larger percentage of winged females (5.66%) compared to <i>S. pupariae</i> (3.98%), and no winged females developed from <i>S. guani</i> or <i>S. sichuanensis</i>. 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.