高温对珍贵绢丝昆虫——天蚕卵巢生长发育的影响

Effect of high temperature on ovarian growth and development in the Japanese oak silkworm, Antheraea yamamai (Lepidoptera:Saturiidae),a precious silkworm

结果表明 ,高温对天蚕 ( Antheraea yamamai)卵巢生长发育有明显的影响。 3、4龄幼虫卵巢生长发育在 2 0～ 2 9℃范围内随温度提高而加快 ,3 2℃下则略有下降 ;5龄幼虫卵巢生长发育在 2 9℃和 3 2℃下明显受阻。在茧蛹期 ,若在刚结茧或化蛹第 1天即经受 3 2℃高温处理 ,卵巢大小及其可溶性蛋白含量多明显小于或低于 2 6℃ ,即其卵巢生长发育明显受阻 ;而在化蛹第 6天开始受 3 2℃高温处理 ,结果则似反之。正因为如此 ,在天蚕制种前 ,建议 3～ 4龄和 5龄幼虫饲育温度各以 2 6～ 2 9℃和 2 0～ 2 3℃为宜 ;结茧至化蛹初期茧蛹保护温度则以 2 6℃为适。此外还测定了 3 2℃高温对卵巢中 DNA和RNA含量的影响。

The result of this study indicated that the effect of high temperature on ovarian growth and development was marked in the Japanese oak silkworm, Antheraea yamamai. Ovarian growth and development in the 3rd and 4th instar larvae increased with an increase of temperature ranging from 20℃ to 29℃,and slightly decreased at 32℃.Whilst it was significantly blocked in the 5th instar larvae at 29℃ and 32℃.As mature larvae or pupae were exposed to 32℃ since the beginning of cocooning or 1st day after pupation,ovarian growth and development was markedly arrested.Both ovarian size and content of soluble protein in ovaries were smaller and lower than those of mature larvae and pupae reared at 26℃,and conversely as exposed to 32℃ since 6th day after pupation.In light of these results,it is suggested that the proper temperature for rearing 3rd～4th and 5th instar larvae which were prepared for egg raising were 26～29℃ and 20～23℃,respectively,and for protecting mature larvae or earlier pupae in cocoons was 26℃.In addition,effect of high temperature on contents of DNA and RNA in ovaries was studied.