关键词: 日本刀角瓢虫；低温贮藏；生物学特性；存活, 生长发育；热激蛋白

Abstract: 【Aim】 This study aims to investigate the biological characteristics of adults and the growth and development of F1 generation of Serangium japonicum at different cold-storage temperatures, so as to determine the optimal cold-storage temperature of S. japonicum adults.【Methods】 S. japonicum adults were stored at different low temperatures (7, 10, 13 and 16 ℃), their survival rates, numbers of eggs laid per female, longevity and daily predation amount against the 4th instar nymphs of Bemisia tabaci, the survival rates and developmental duration of F1 generation of S. japonicum, and the relative expression levels of the heat shock protein genes Hsp70 and Hsp90 in S. japonicum adults were determined at 10 d after storage by qRT-PCR. 【Results】At 10 d after S. japonicum adults were stored at 16 ℃, their survival rate, female and male adult longevity, number of eggs laid per female and daily predation amount, and the survival rate of F1 generation were not significantly different from those of the control stored at 26 ℃ (survival rate: 99% vs 100%; female adult longevity: 110.65 d vs 106.87 d; male adult longevity: 123.12 d vs 108.79 d; number of eggs laid per female: 399.19 grains vs 422.63 grains; daily predation amount: 34.70 individuals vs 31.95 individuals; F1 progeny survival rate: 8039% vs 94.12%); but the developmental duration of F1 generation was significantly shorter than that of the control (17.33 d vs 18.89 d). At 10 d after coldstorage, all S. japonicum adults died when stored at 7 ℃, when stored at 10 ℃, their survival rate and number of eggs laid per female and the survival rate of F1 generation were significantly affected, and when stored at 13 ℃, the number of eggs laid per female was significantly affected. Various cold-storage temperatures induced the up-regulation of the expression levels of both Hsp70 and Hsp90 in S. japonicum adults at 10 d after storage, and the lower the temperature, the higher the relative expression levels. The relative expression levels of Hsp70 and Hsp90 in the treatment group of 10 ℃ were 7.06- and 2.33-fold, respectively, as high as those in the control.【Conclusion】 Combining the above results, the optimum cold-storage temperature for S. japonicum adults is 16 ℃, and the heat shock proteins Hsp70 and Hsp90 may play a protective role in the response to cold stress in S. japonicum adults.

Key words: Serangium japonicum, cold-storage, biological characteristics, survival, growth and development, heat shock protein