玉米螟卵龄对玉米螟赤眼蜂和松毛虫赤眼蜂种间竞争的影响

Effects of Ostrinia furnacalis egg age on interspecific competition between Trichogramma ostriniae and Trichogramma dendrolimi

室内观察了松毛虫赤眼蜂和玉米螟赤眼蜂寄生亚洲玉米螟卵的寄生行为,以及两种赤眼蜂在单独和竞争情况下的寄生及其子代蜂受寄主卵龄的影响。结果发现:松毛虫赤眼蜂完成1次寄生所需时间显著短于玉米螟赤眼蜂,而产卵次数占总寄生次数的比例(40.16%)显著低于玉米螟赤眼蜂(66.26%)。单独寄生时,玉米螟卵龄对玉米螟赤眼蜂的子代雌蜂数和子代蜂存活无显著影响,但对松毛虫赤眼蜂具有显著影响,且死亡蜂数量随卵龄增大而增多。在竞争情况下,两种赤眼蜂子代总雌蜂数均增加;寄生6h和36h玉米螟卵产出的子代蜂显著小于单独寄生时的子代蜂;寄生12h卵的子代蜂死亡数(21头)显著高于寄生其他龄期的卵,但在其他卵龄间无显著差异。

The parasitism behavior of Trichogramma ostriniae and T. dendrolimi on Ostrinia furnacalis and the effects of host egg age on offspring of the two parasitoids were investigated in the laboratory. The results indicated that time consumed for completing one parasitization for T. dendrolimi was significantly shorter than that for T. ostriniae, whereas the percentage of parasitization （ 66. 26%） with oviposition was significantly higher for T. ostriniae than that,40. 16%,for T. dendrolimi. The number of female offspring produced was not significantly affected by host egg age when O. furnacalis eggs were exposed to only T. ostriniae,whereas it was significant when O. furnacalis eggs were exposed to only T. dendrolimi. Competition increased the number of female offspring wasps in all host egg ages tested,but the body size of offspring was significantly smaller than that when 6 h or 36 h host eggs were exposed only to T. ostriniae or T. dendrolimi. When the host eggs were exposed to T. ostriniae,the number of dead offspring was not significantly affected by host age,whereas it was significantly affected and increased with host ages for T. denrolimi. When host eggs were exposed to two wasp species,the number of dead offspring wasp （ 21） was significantly more in treatment with 12 h host egg than that with other three host ages,among those three host ages the numbers of dead offspring wasp were not significantly different.