Responses of Harmonia axyridis(Pallas)(Coleoptera: Coccinellidae)adults to cold acclimation and the related changes of activities of several enzymes in their bodies
In order to clarify the effects of cold acclimation on cold tolerance of adlult Harmonia axyridis (Pallas)(Coleoptera:Coccinellidae),we investigated the survival rate,supercooling point(SCP),water content and reproduction capability of adults under low temperature in the laboratory condition.Adults of H.axyridis were cold acclimated at 5℃ successively flor 1,3,5 and 10 d prior to cold stress.The results showed that the survival rate of the adults exposed to-50℃ for 3 d was improved from 46% of the control (without prior cold stress)to 60% and 67% when adults were acclimated flor 3 d and 5 d,respectively,but decreased to 51% after the cold acclimation for 10 d.Returning of the adults to 25℃ caused a loss of cold acclimation within 7 d.The SCP and the water content decreased as the duration of cold acclimation prolonged.Short-term(5,10 d)exposure to 5℃ did not decrease the SCP even though it significantly decreased water content in the body.The pro-oviposition period of the female was delayed after acclimation.Acclimation significantly decreased the fecundity within 72 h,but did not affect the number of eggs laid in the first cluster.The effects of cold acclimation on several enzyme activities were examined.and the results showed that superoxide dismutase(SOD)and catalase(CAT)activities increased whereas lactate dehydrogenase(LDH)and Na~+,K~+-ATPase activities decreased after cold acclimation.These resultsindicate that cold acclimation is a complex physiological and biochemical process,which is very important to the survival and reproduction of H.axyridis.
国家科技期刊平台
NSTL
万方数据
维普
