寄主龄期对半闭弯尾姬蜂生物学特性的影响

The Effect of Host Age on Biological Characteristics of Diadegma semiclausum

在24℃下研究了小菜蛾幼虫龄期对半闭弯尾姬蜂子代发育、存活及雌蜂寄生能力的影响。结果表明,寄生不同寄主龄期的半闭弯尾姬蜂从卵发育到结茧的历期存在显著差异,寄生于4龄幼虫的个体比寄生2、3龄幼虫的个体发育显著要快,但结茧至成蜂羽化的历期无显著性差异;寄生不同龄期小菜蛾幼虫的寄生蜂的结茧率、羽化率无显著差异;寄生各个龄期的后代雌蜂在羽化当天的寄生能力没有差异,但寄生3龄小菜蛾幼虫羽化出的蜂每雌总产卵量显著高于寄生2龄和4龄幼虫羽化出的蜂,雌蜂的寿命也比寄生2龄和4龄的显著要长。

The effects of host larval instars of Plutella xylostella at initial parasitization on developmental time, survival, and parasitism rate of the female wasp Diadegma semiclausum were investigated at 24 ℃ in laboratory. Results showed that the parasites that parasitized initially in the 4th instar host larvae had significantly shorter developmental duration from egg to cocoon formation than those which parasitized initially in the 2nd or 3rd instar larvae, however, there were no significant difference in the developmental duration from cocoon formation to adult emergence, percentage of cocoon formation and adult emergence, irrespective of host instar at initial parasitization. Although the offspring adults from the three different host instars at initial parasitization had no significant difference in the parasitism capacity in the first day post-emergence, the female adults, which derived from parasitized 3rd instar larvae, laid more eggs in their lifetime and had longer longevity than those from parasitized 2nd and 4th instars larvae.