Plasticity of cold and heat stress tolerance induced by hardening and acclimation in the melon thrips.

[Display omitted] • This study tested phenotypic changes in heat and cold tolerance of Thrips palmi. • Rapid heat hardening at 35 °C slightly increased CTmax but decreased it at 31 °C. • Heat acclimation for 2 and 4 days significantly increased CTmax at 35 °C. • Cold hardening and acclimation increased cold tolerance. • Space for heat stress induction is narrower than for cold stress induction. Extreme temperatures threaten species under climate change and can limit range expansions. Many species cope with changing environments through plastic changes. This study tested phenotypic changes in heat and cold tolerance under hardening and acclimation in the melon thrips, Thrips palmi Karny (Thysanoptera: Thripidae), an agricultural pest of many vegetables. We first measured the critical thermal maximum (CT max) of the species by the knockdown time under static temperatures and found support for an injury accumulation model of heat stress. The inferred knockdown time at 39 °C was 82.22 min. Rapid heat hardening for 1 h at 35 °C slightly increased CT max by 1.04 min but decreased it following exposure to 31 °C by 3.46 min and 39 °C by 6.78 min. Heat acclimation for 2 and 4 days significantly increased CT max at 35 °C by 1.83, and 6.83 min, respectively. Rapid cold hardening at 0 °C and 4 °C for 2 h, and cold acclimation at 10 °C for 3 days also significantly increased cold tolerance by 6.09, 5.82, and 2.00 min, respectively, while cold hardening at 8 °C for 2 h and acclimation at 4 °C and 10 °C for 5 days did not change cold stress tolerance. Mortality at 4 °C for 3 and 5 days reached 24.07 % and 43.22 % respectively. Our study showed plasticity for heat and cold stress tolerance in T. palmi , but the thermal and temporal space for heat stress induction is narrower than for cold stress induction. [ABSTRACT FROM AUTHOR]