Thermotolerance of the spotted-wing fly, Drosophila suzukii: effect of sex and anesthesia

PUTERO, F.; MENSCH, J.; SCHILMAN, P.E.

Simposio; International Symposium on the Environmental Physiology of Ectotherms and Plants (ISEPEP2022); 2022

The spotted-wing fly, Drosophila suzukii, is a pest insect species with increasing interest in its thermotolerance traits. However, most studies focus only on survival to different time exposures to extreme temperatures, and mainly in female flies. Furthermore, it has not been analysed yet if anesthesia used for its manipulation affects these measurements. We proposed to perform three standard thermotolerance assays: Critical temperatures minimum (CTmin) and maximum (CTmax), and chill-coma recovery time (CCRT) on both, female and male flies. In addition, we analyzed the effects of anesthesia by brief exposures to: cold (1 minute at -7C), anoxia by CO2 or N2 (1 minute). Critical temperatures were measured using a dynamic method starting at 25ºC, followed by a ramp of increasing (CTmax; using "thermolimit respirometry") or decreasing temperature (CTmin) at 0.25 or -0.25C min-1 respectively. For CCRT measurements, insects were exposed to ca. 0C for 14 hours, and then time to recover was recorded. Results showed a significant higher cold and heat tolerance in females than males, in terms of their CTmin and CTmax, respectively. Cold anesthesia shows a signicant decrease of 0.60ºC in CTmax for both sexes (37.250.79) relative to all others groups (37.740.53 control, 37.750.78 N2 and 37.710.48 CO2). No effects of sex and anesthesia were showed in CCRT. We conclude that cold anesthesia seems to have detrimental eects on heat tolerance, and females have broader tolerance range than males, which could help them to survive extreme temperatures in temperate regions.