Thermal Requirements of Two Egg Parasitoids of Brown Stinkbug Euschistus heros (Hem.: Pentatomidae)

Temperature is the abiotic factors that strongly influence the biology and behavior of insects. Thus, we assessed the development of the egg parasitoids, Ooencyrtus submetallicus and Telenomus podisi, parasitizing eggs of the brown stinkbug, Euschistus heros, at different temperatures, in addition to estimating the average number of generations using temperature records for seven representative soybean producing regions in Brazil. The comparative biology study conducted evidenced that O. submetallicus and T. podisi had similar percentages of parasitism and emergence, life cycle duration (egg-adult), and longevity. The sex ratio and the number of adult parasitoid emerged per parasitized egg was superior for O. submetallicus. The study of thermal requirements evaluated temperatures of 16, 19, 22, 25, 28, 31, and 33 °C. Ooencyrtus submetallicus and T. podisi developed at temperatures between 16 and 31°C. The lower temperature (Tb) threshold for O. submetallicus and T. podisi was 9.3° and 6.7°C, while the thermal constant (K) was 336.9 and 272.7 degree days, respectively. The estimated average number of generations per year for both parasitoids was greater than the pest E. heros. Ooencyrtus submetallicus and T. podisi exhibited the same biological capacity to parasitize and to develop parasitizing E. heros eggs under laboratory studied conditions. The temperature range between 16° and 33 °C was favourable for the development of both parasitoids parasitizing E. heros eggs.