Effect of different temperature scenarios on survival probability, parasitism success, and offspring tibia length of Pachycrepoideus vindemiae (PV) and Trichopria drosophilae (TD)

Survival probability, parasitism success as well as offspring sex ratio and left and right hind tibia lengths of two candidate parasitoids of spotted wing drosophila Drosophila suzukii (Diptera: Drosophilidae), Trichopria drosophilae (Hymenoptera: Diapriidae; TD) and Pachycrepoideus vindemiae (Hymenoptera: Pteromalidae; PV) females and males were assessed under different temperature scenarios. The control scenario (SCt-28–10 °C) featured a daily temperature cycle with a maximum of 28 °C day and a minimum of 10°C night temperature. In addition, females were exposed for 48 h to three elevated temperature scenarios (SEt) with a maximum of 30°C, 32°C and 34°C and a minimum of 12°C, 14°C and 16°C, respectively (SEt-30–12 °C, SEt-32–14 °C, and SEt-34–16 °C). After exposure to elevated temperature scenarios, all females were transferred back to a climate chamber running at SCt 28-10 °C. Throughout the experiment, droplets of honey were provided as food for adult wasps. Survival probability of adult parasitoids was assessed daily for the first 4 days after exposure to the respective elevated temperature scenario. The assessment was then performed every 3rd to 4th day for a total period of 29 days. For assessment of parasitism success, offspring sex ratio and hind tibia length, females were offered Drosophila suzukii pupae for parasitization for 24 h under SCt 28-10 °C after exposure to the different elevated temperature scenarios. Pupae were kept in the control scenario (SCt 28-10 °C) for 6 weeks in order to complete their development.