The effect of acclimation on heat tolerance of Lasioderma serricorne (Fabricius) (Coleoptera: Anobiidae)

Lasioderma serricorne (Fabricius) (Coleoptera: Anobiidae) is an important economic insect of various stored products worldwide. With the restricted use of methyl bromide and the increasing negative effects of repeated use of phosphine fumigation, heat treatment becomes the main approach to control stored-product insects. We investigated effect of the acclimation to sublethal high temperature of 36 °C and 42 °C for different times on heat tolerance of L. serricorne adults, pupae, larvae, and eggs to lethal high temperature of 50 °C in laboratory. The acclimation of L. serricorne pupae, larvae, and eggs, but not adults, to 36 °C improved their survival when exposed to lethal high temperature of 50 °C. The acclimation of all life stages of L. serricorne to 42 °C significantly improved their survival when exposed to 50 °C. For eggs, larvae, and adults, the protective effectiveness of acclimation to 42 °C was much more profound than that of to 36 °C. LT50 and LT90 of all life stages increased with increasing acclimation time to 42 °C in general. The LT50 of L. serricorne adults, pupae, larvae, and eggs acclimation to 42 °C for 20 h were 2.2, 2.2, 3.4, and 4.8 times higher than that of insects without acclimation, respectively. The results suggest that acclimation to sublethal high temperatures can significantly improve the heat tolerance of L. serricorne by the means of increasing their survival when confronting lethal high temperatures. In the face of global warming, the protective effects induced by acclimation to sublethal high temperatures should be fully considered when design or apply heat treatment to control L. serricorne.