Effects of temperature on development, reproduction and size ofTrichogramma achaeae: implications for biological control

The performance of biological control agents (BCAs) in outdoor crops is strongly regulated by ambient temperature. Understanding the thermal biology of BCAs and manipulating their thermal performance could improve biological control efficacy. In this study, the effects of temperature on several life history parameters (longevity, fecundity, development time, wing size) of the recently commercialised egg parasitoid Trichogramma achaeae Nagaraja & Nagarkatti (Hymenoptera: Trichogrammatidae) was examined. First, parasitoids were reared at 23 °C and tested in the laboratory at four constant temperatures (15, 20, 25 and 30 °C). Results demonstrated that temperature significantly altered all above parameters. Second, developmental acclimation was applied to manipulate the laboratory performance. Parasitoids were allowed to develop at either of the above four temperatures and their performance were compared at 23 °C. Results showed that developmental acclimation had a significant impact on fecundity, development time and wing size but not on female longevity. Our results have implications for improving the performance of T. achaeae in mass production and for its application for biological control under different thermal conditions. Highlights The temperature dependent performance of Trichogramma achaeae was characterised Acclimation significantly influenced fecundity, development and body size The overall performance was not improved by acclimation The female fecundity could be a proxy for the overall performance of T. achaeae