Effects Of Acclimation To High Temperature On Thermal Stress Ecological Adaptability Of Tribolium Castaneum (Herbst)

Tribolium castaneum(Herbst)is one of the main stored-product insects.The influence of acclimation to sublethal temperature(36 and 42 ?)on the mortality and developmental durationof T.castaneum adults,pupae,larvae,and eggsexposed to 50 ? was investigated,respectively.The effect of acclimation to sublethal temperature onthe fecundity of T.castaneum,the developmental duration and survival rate(%)of F1 progeny,population of T.castaneum,and the activity of protective enzymes of T.castaneum adults and larvae were also investigated,respectively.Determining the effects of acclimation to high temperature on thermal stress ecological adaptability of T.castaneumcan provide a theoretical basis for developing rational heat treatment program and improving the control effectiveness of heat treatment.The main results are as follows:Under the same conditions of acclimation,the mortality of four developmental stages of T.castaneum increased significantly with the increasing exposure time.Acclimation to sublethal temperatures enhanced their abilities of adaption to the high temperature stress environment.The influence of acclimationto 42 ? was apparently greater than that of acclimation to 36 ?.The most influential acclimation times to 42 ? on mortality of T.castaneum eggs,larvae,pupae,and adults were 15,5,5,and 5 h,respectively,and the most influential acclimation times to 36 ? on mortality of T.castaneum eggs,larvae,pupae,and adults were 5,10,10,and 15 h,respectively.The abilities of adaption to the high temperature stress environment was different between four developmental stages of T.castaneum.The heat tolerance level of eggs and larvae was lower than that of adults and pupae.The developmental duration of eggs,larvae and pupae was extended,and the survival rate of different developmental stages was decreased with the increasing exposure time.The survival rate of all developmental stages of T.castaneum with sublethal temperatures acclimation was higher than that of insects without acclimation.In addition,the developmental duration of larvae with acclimation to 42 ? was decreased,the developmental duration of insects with acclimation to sublethal temperatures was extended.The developmental duration of different stages and mortality of insects with acclimation to 42 ? were lower than that of insects with acclimation to 36 ?.Compared with the fecundity and egg-to-adult survival rate of T.castaneum without acclimation(acclimation time was 0 h),the fecundity and egg-to-adult survival rate of acclimated T.castaneum(acclimation time was 5,10,15 h)decreased significantly.The developmental duration of F1 progeny that produced by acclimated T.castaneum extended with increasing acclimation times,and the survival rate of eggs and larvae decreased with increasing acclimation times.The developmental duration of eggs and pupae of F1 progeny that produced by T.castaneum acclimated to 42 ? was longer than that acclimated to 36 ?,while the mortality of different developmental stages of F1 progeny that produced by T.Castaneum acclimated to 42 ? was lower than that acclimated to 36 ?.Compared with the heat tolerance of F1 progeny that produced by T.castaneum without acclimation,the heat tolerance of F1 progeny that produced by acclimated T.castaneum increased significantly.The mortality of F1 progeny by T.castaneum increased significantlywith the extension of processing time,The heat to lerance of F1 progeny that produced by T.castaneum acclimated to 42 ? was higher than that acclimated to 36 ?,and the most heat tolerance acclimation time to 42 ? was 10 h.After acclimation to sublethal temperatures,the population number of T.castaneum adults decreased significantly.The population of T.castaneum adults increased rapidly in the observation time from 35 to 56 days.Under the same conditions of acclimation,the stability population of T.castaneum adults with discarding the original mating pairs after 2 weeks was higher than that reserved the original mating pairs.The stability population of T.castaneum adults with acclimation of 15 h was the lowest among other acclimation conditions,and the time required to reach stability population was minimum.The stability population of T.castaneum adults acclimation to 42 ? was lower than that acclimation to 36 ?.The influence of acclimation times and temperatures on the activity of protective enzymes of T.castaneum were variable.With the extension of acclimation time(acclimation temperature was 36 ?),the activity of SOD of larvae enhanced,the activity of POD increased at first and then decreased,and the activity of CAT decreased.With the extension of acclimation time(acclimat ion temperature was 42 ?),the activity of SOD of adults increased at first and then decreased,the activity of POD and CAT decreased.After acclimation to 36 ? and 42 ?,the activity of SOD of adults was significantly lower than larvae,while the activity of POD and CAT of adults was significantly higher than larvae.