Preimaginal developmental time of two egg parasitoids and their host searching efficiency

Abstract

ABSTRACTWhen searching for hosts, parasitoids may experience competition between adults exploiting the same host (extrinsic), or between larvae developing inside the host (intrinsic competition). Differences in competitive abilities like host location and resource utilisation promote coexistence. In this sense, extrinsically superior parasitoids better locate hosts, and intrinsically superior ones can have a shorter preimaginal development, which gives them a competitive advantage in physiological suppression against its competitor. Piezodorus guildinii (Hemiptera: Pentatomidae) is an important soybean pest, and its main natural enemies are egg parasitoids Telenomus podisi and Trissolcus urichi (Hymenoptera: Platygastridae). We compared the ability of wasps to locate host eggs, and larval development time of both parasitoids. Both species took the same amount of time to find and contact eggs, and to start parasitising them. There were no differences in average development time of larvae, pupae, and the entire preimaginal period. Both parasitoid species compared in this study are closely related, having very similar life history strategies. These factors could have covered up other aspects of the host foraging abilities of each species, which can make differences between them when searching for hosts in the field. Moreover, searching abilities of both species could be similar under laboratory conditions but different under field conditions. Understanding competitive interactions between parasitoids is important to improve the biological control of the pest.