寄主和温度对半闭弯尾姬蜂饲养的影响

Effect of host and temperature on reproducing of Diadegma semiclausum Hellen

【目的】对半闭弯尾姬蜂Diadegma semiclausum Hellen室内饲养过程中影响繁殖的寄主和温度这两个因子进行研究，得到半闭弯尾姬蜂室内繁殖饲养时的最佳寄主数量和温度。【方法】在室内设置不同小菜蛾Plutella xylostell（L．）幼虫数量和幼虫龄期条件下，研究了幼虫数量和龄期对半闭弯尾姬蜂寄生率的影响，以及设置6个恒温（15、20、22、25、27和30℃）条件下研究了温度对半闭弯尾姬蜂发育历期、羽化率、性比的影响。【结果】小菜蛾幼虫数量在30-90头范围内对半闭弯尾姬蜂寄生率无影响，但超过90头后，寄生率明显下降；半闭弯尾姬蜂对小菜蛾幼虫龄期有选择性，对2，3龄小菜蛾幼虫的寄生率高于4龄幼虫；半闭弯尾姬蜂各个虫态的发育历期随着温度的升高而明显缩短，当温度升高到30℃，卵至蛹的发育历期比27℃的发育历期有所缩短，但化蛹后不能正常羽化；在15～22℃的温度范围内，半闭弯尾姬蜂的羽化率和性比随着温度的升高而增加，在22—27℃的范围内，半闭弯尾姬蜂的羽化率和性比随着温度的升高而降低。【结论】在室内饲养扩繁半闭弯尾姬蜂时应选用2～3龄的小菜蛾幼虫，每对半闭弯尾姬蜂提供的小菜蛾幼虫数量为40～50头；以22℃为最适合温度。

[Obiectives] The effect of host and temperature on the reproduction of Diadegma semiclausum Hellen was studied, and the optimal larvae number, larval instars of Plutella xylostell （L.） and temperature for the reproduction of this species determined. [Methods] The effect of larvae number and instars of P xylostella on the parasitization of D. semiclausu and the effect of temperature on the development time, emergence ratio and sex ratio of D. semiclausum were studied at six constant temperatures （15, 20, 22, 25, 27, 30℃） in the laboratory. [Results] Results show that the parasitization of D. semiclausum decreased with the increase of larvae numbers of P xylostell from 30-90, but this decrease was not statistically significant. Parasitization significantly decreased when the number of larvae exceeded 90. D. semiclausum could parasitize the 2nd, 3rd and, 4th instars of DBM larvae, however, parasitization parasitization of the 2^ndand 3^rd instars was significantly higher than the 4th. Developmental time, emergence ratio and sex ratio ofD. semiclausum were observed. Results show that the developmental time of an entire generation decreased significantly with increasing temperature from 15-27℃ and that pupae failed to develop when the temperature reached 30℃. The emergence ratio and sex ratio increased with increasing temperature from 15-22 ℃, and decreased with increasing temperature from 22-27 ℃.