Anoxia blocks thermotolerance and the induction of rapid cold hardening in the flesh fly, Sarcophaga crassipalpis

Abstract

Abstract. Anoxia induced by nitrogen or carbon dioxide, or hypoxic/hypobaric conditions generated by a partial vacuum sensitizes red‐eye pharate adults of Sarcophaga crassipalpis Macquart to a high temperature exposure that is normally nonlethal (40d̀C for 2–3 h). Thermotolerance induced by a2h exposure to 40d̀C (under aerobic conditions) doubles the pharate adults' tolerance to 45d̀C but provides no protection against a combined exposure to 45d̀C and anoxia, and only modest protection against a combined exposure to 40d̀C and anoxia. Under aerobic conditions, exposing pharate adults to 0d̀C for 2 h increases their tolerance to ‐10d̀C (rapid cold hardening). Rapid cold hardening at 0d̀C is not induced under anoxia. These results imply that tolerance to high temperatures and rapid cold hardening are dependent on aerobic processes and suggest that certain forms of temperature stress can be further exacerbated with anoxia.