异色瓢虫成虫冷驯化反应及体内几种酶活力的相关变化

Responses of Harmonia axyridis (Pallas) (Coleoptera:Coccinellidae) adults to cold acclimation and the related changes of activities of several enzymes in their bodies

为明确冷驯化反应对异色瓢虫Harmonia axyridis(Pallas)实验种群成虫耐寒性及其生殖能力的影响,本研究测定了成虫低温存活率、过冷却点(supercooling point,SCP)、体内含水量及雌虫繁殖能力等。结果表明:冷驯化(在5℃下诱导3d,5d)后,成虫再在-5℃下暴露3d的存活率由对照(预先未进行冷驯化)的46%分别提高至60%和67%,而诱导10d后的存活率(51%)反而下降。冷驯化效应在其成虫转移至饲养条件下7d后就消失。随着低温诱导时间的延长过冷却点及体内含水量均呈现下降趋势,短时间(5,10d)的诱导不能使成虫的SCP明显降低,但可以使含水量极显著下降。冷驯化后异色瓢虫雌虫产卵前期延长;虽然冷驯化对雌虫首次产卵量没有影响,但是随着诱导时间的延长连续观察72h内单头雌虫累计产卵量却降低。冷驯化过程中成虫体内几种酶活力的检测结果表明:两种细胞保护酶超氧化物歧化酶(SOD)与过氧化氢酶(CAT)活性升高,与新陈代谢有关的乳酸脱氢酶(LDH)及Na+,K+-ATP酶活性却降低。结果显示,低温胁迫前异色瓢虫成虫经过不同时间的诱导后有可能提高其低温抵抗能力,而且冷驯化诱导成虫耐寒性增加是一种复杂的生理生化过程,这一过程对其生存和繁殖具有重要的适应意义。

In order to clarify the effects of cold acclimation on cold tolerance of adult 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 11. axyridis were cold acclimated at 5℃ successively for 1, 3, 5 and 10 d prior to cold stress. The results showed that the survival rate of the adults exposed to -5℃ for 3 d was improved from 46% of the control （without prior cold stress） to 60% and 67% when adults were acclimated for 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-teim （5, 10 d） exposure to 5℃ did not decrease the SCP even though it significantly decreased water content in the body. The pre-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 duster. The effects of cold acclimation on several enzyme activities were examined, and the results showed that superoxide disnautase （SOD） and catalase （CAT） activities increased whereas lactate dehydrogenase （LDH） and Na＋, K＋-ATPase activities decreased after cold acclimation. These results indicate that cold acclimation is a complex physiological and biochemical process, which is very important to the survival and reproduction of H. axyridis.