Effects of host size, maternal state, and developmental time on the adult size in a parasitoid

Body size is a crucial characteristic of many animal species because it affects many fitness-related traits. Parasitoids are important insects that are well-known biological control agents of pests, and it is favourable to obtain larger parasitoids that increase fitness and benefit wild application. Host size is thought to be one of the most crucial factors influencing the body size and has received widespread attention. Here, in an egg parasitoid Anastatus disparis, we found that the body size of female significantly increased with increasing host size, while host size did not significantly affect male body size. In addition to the widely known factor of host size, both female and male offspring size significantly increased with increasing maternal size, and female offspring produced by younger mothers were larger in size. However, inconsistent with common knowledge, the body sizes of both females and males appears to increase when the total development time from egg to adult eclosion decreases. Although all the developmental temperatures of the offspring were the same, the development time significantly differed and was significantly affected by maternal status. The male offspring produced by larger females have shorter development times, and the female offspring produced by older females have longer development times. Consequently, our results suggested that the effect of maternal status on offspring size may be mediated by influencing development time. Furthermore, A. disparis is considered potential biological control agent for several Lepidoptera pests, and our results provide further guidance for mass rearing indoors and pest control in the wild.