35℃下烟青虫夏滞育率、蛹重及代谢速率的变化

The summer diapause rate, pupal weight, and metabolic rate of Helicoverpa assulta at 35℃

【目的】本文旨在研究烟青虫Helicoverpa assulta在高温下的滞育的发生和生理的变化。【方法】高温可以诱导不同龄期的烟青虫进入夏滞育,本实验在35℃,L︰D=16︰8条件诱导3龄、4龄、6龄、预蛹期的烟青虫夏滞育,并比较研究了滞育蛹和非滞育蛹代谢水平的差异。【结果】研究结果发现,在35℃下,烟青虫的3龄、4龄、6龄幼虫与预蛹期的夏滞育率分别为25.96%、25.71%、22.76%、11.31%,3个幼虫期的滞育率显著高于预蛹期滞育率。不同龄期的滞育诱导中,雄性的夏滞育率都明显高于雌性夏滞育率。并且,滞育蛹显著比未滞育蛹重。对滞育蛹和未滞育蛹的失重动态与呼吸代谢速率比较研究,结果发现:夏滞育虫蛹的失重曲线平缓,显著低于未滞育蛹;并且呼吸代谢速率曲线平缓且显著低于未滞育蛹。【结论】研究表明,高温能诱导烟青虫能进入夏滞育,并且夏滞育蛹能通过维持低的代谢水平来度过不利环境,具有一定的生态适应意义。

[Objectives] To determine the occurrence of summer diapause and its associated physiological changes in Helicoverpa assulta exposed to high temperature. [Methods] Summer diapause in H. assulta can be induced by high temperature at different larval stages. In this study, we recorded the diapause rate of 1-1. assulta under 35℃ and L16 ： D8 beginning at the third, fourth, sixth larval and pupal stage and compared the pupal weight and metabolic rate of diapausing and non-diapausing pupae. [Results] The summer diapause rates were 25.96% 、 25.71%, 22.76%, 11.31%, for third, fourth, sixth, and prepupal stage, respectively. The results show that the diapause rate of the third, fourth and sixth stages was significantly higher than that of the prepupal stage. Furthermore, the summer diapause rates of males were significantly higher than those of females for each tested stage. The pupal weights of diapausing pupae were significantly heavier than those of non-diapausing pupae. We comparatively measured the metabolic levels, using two indices, i.e., body weight loss and respiratory rate, of diapausing and non-diapausing pupae. The weight loss curves of the diapausing pupae were significantly lower than those of the non-diapausing pupae. Moreover, the respiratory rate curve of diapausing pupae was significantly lower than that of non-diapausing pupae. IConclusion] The results indicate that diapausing pupae can significantly reduce their metabolism and delay their development under high temperature to survive adverse environmental conditions.