耐低湿松毛虫赤眼蜂的筛选及在柞蚕卵内的发育过程

Screening of Trichogramma dendrolimi under low humidity stress and its development in Antheraea pernyi eggs

松毛虫赤眼蜂(Trichogramma)广泛应用于多种鳞翅目害虫的生物防治,但是西北干旱地区可利用蜂种较少,因此耐低湿松毛虫赤眼蜂的驯化非常必要,同时耐低湿松毛虫赤眼蜂在柞蚕卵内的发育过程研究对其规模化扩繁有重要意义。本研究通过低湿胁迫筛选出耐低湿松毛虫赤眼蜂种系,测定其对柞蚕卵的寄生率和出蜂率,并观察了50%湿度条件下的发育过程。结果表明,松毛虫赤眼蜂的寄生率和出蜂率随相对湿度下降呈降低趋势;且经低湿胁迫处理后,不会导致松毛虫赤眼蜂产生形态上的明显差异。在25±0.5℃条件下,耐低湿松毛虫赤眼蜂在柞蚕卵内的发育历期为10 d,其中卵期30 h,幼虫期24 h,预蛹期72 h,蛹期106 h,在产卵后240 h时,赤眼蜂羽化为成虫,羽化后即在柞蚕卵内完成交配,最后咬破柞蚕卵壳钻出,与70%湿度(对照)无差异。表明低湿胁迫可降低松毛虫赤眼蜂寄生率和出蜂率,但不会导致生长发育和形态上的明显差异。

Trichogramma dendrolimi is widely used in biological control of most lepidopteran pests.But there are few available bee species in the arid areas of Northwest China,so the domestication of Trichogramma dendro⁃limi with low humidity tolerance is very necessary.At the same time,the study on the development process of Trichogramma dendrolimi in eggs of tussah is of great significance for its large⁃scale propagation.In order to achieve the application requirements of agriculture,this study selected out a low humidity tolerant strain of T.dendrolimi through low humidity press method,then measured its parasitism rate and bee emergence rate on the eggs of tussah(Antheraea pernyi),and observed the development process under 50%relative humidity condition.The results showed that the parasitism rate and the emergence rate of T.dendrolimi decreased with the decrease of relative hu⁃midity.After the treatment of low humidity stress,the morphology of T.dendrolimi could not be significantly differ⁃ent.Under the condition of(25±0.5)℃,the development period of T.dendrolimi in the egg of tussah was 10 d,including the egg stage of 30 h,larval stage of 24 h,prepupal stage of 72 h,and pupal stage of 106 h.At 240h after oviposition,T.dendrolimi emerged into an adult,and mating was completed in the egg of tussah,finally bitted on tussah eggs shell and get out.The whole process was same to nature individuals with 70%humidity(control).In conclusion,low humidity stress can reduce the parasitism rate and emergence rate of T.dendrolimi,but does not lead to significant differences in individual growth,development and morphology.