Acclimation Effects of Natural Daily Temperature Variation on Longevity, Fecundity, and Thermal Tolerance of the Diamondback Moth (Plutella xylostella)

SIMPLE SUMMARY: Diurnal, monthly, or seasonal temperatures can fluctuate substantially. Daily temperature amplitudes (DTAs) can significantly impact the traits of insects but there is limited evidence from the natural environment. Therefore, we studied the acclimation effects of DTA on the longevity, total fecundity, early fecundity, and thermal tolerance of adult diamondback moths (Plutella xylostella) under environmental conditions. The longevity, total fecundity, early fecundity, and heat thermal tolerance of adults significantly changed under different DTAs. These findings highlight the effects of DTA on the acclimation response in the P. xylostella phenotype, and DTA should be incorporated into prediction models for assessing insect populations and the effects of climate change. ABSTRACT: Daily temperature amplitudes (DTAs) significantly affect the ecological and physiological traits of insects. Most studies in this field are based on laboratory experiments, while there is limited research on the effects of changes in DTA on insect phenotypic plasticity under natural conditions. Therefore, we studied the acclimation effects of DTA on the longevity, total fecundity, early fecundity, and the thermal tolerance of adult diamondback moths (Plutella xylostella L.) under naturally occurring environmental conditions. As DTAs increased, male longevity and total fecundity decreased, and early fecundity increased. An increase in DTA was significantly associated with the increased heat coma temperature (CT(max)) of both males and females, but had no significant effect on their cold coma temperature (CT(min)). Our findings highlight the effects of DTA on the acclimation response of P. xylostella and emphasize the importance of considering DTA in predicting models for assessing insect populations and the effects of climate change.