Thermal tolerance of Frankliniella occidentalis: Effects of temperature, exposure time, and gender

Abstract

Western flower thrips (WFT), Frankliniella occidentalis, is an invasive worldwide pest that causes great economic loss. Temperature plays an important role in shaping insect distributions. In this study, we report the survival rates of 3-day-old WFT exposed to rapid changes in extreme high and low temperatures. Temperature, exposure time, and gender all significantly affected the survival of adult WFT, with the lowest survival associated with more extreme temperatures and/or longer exposures. The temperature required to kill 50% of exposed WFT individuals (LT 50) decreased with extended exposure time, but females were more tolerant to extreme temperature than males. Investigation of rapid cold or heat hardening suggested that a short prior exposure to a sub-lethal low or high temperature increased WFT survival during a subsequent exposure to a lethal temperature. Tolerance of extreme temperatures and an ability to undergo rapid hardening are of great ecological relevance in determining the geographic distribution of WFT, allowing it to survive better in temporary bouts of extreme temperature stress. Our findings provide useful information on the environmental limits on the distribution of WFT, which have implications for control of this pest.