蝇蛹金小蜂对桔小实蝇蛹体型大小的产卵选择及子代生长发育表现

Effects of body size of Bactrocera dorsalis pupae on oviposition and offspring developmental preference of Pachycrepoideus vindemmiae

为探究寄主质量对寄生蜂寄生的影响,在室内研究了桔小实蝇蛹体大小对蝇蛹金小蜂寄生选择和子代生长发育的影响。采用饥饿法处理桔小实蝇三龄幼虫获得体型(用体质量表示)差异较大的寄主蛹,供蝇蛹金小蜂选择寄生,观察寄生蜂寄生不同质量寄主的子代数量、发育历期、性比和成虫寿命。结果表明,蝇蛹金小蜂对寄主大小有显著的选择性,蝇蛹金小蜂显著偏好寄生体型较小的寄主蛹,而且随着寄主体型的增大,其雌性比率增大;然而,桔小实蝇蛹体大小不影响蝇蛹金小蜂子代的发育历期和寿命。由此可见,蝇蛹金小蜂母蜂能够根据寄主质量来调节子代的数量和性比,以最大优化子代的适合度。

In order to understand whether the influence of host＇ s body size on the preferential oviposition of mother parasitoids and the performance of progeny parasitoids, the effects of Bactrocera dorsalis pupae on oviposition and development of Pachycrepoideus vindemmiae were studied in laboratory. The pupae of B. dorsalis were manipulated by starvation at third instar larval stages to obtain host pupae with wide variation in body size. The results showed that P. vindemmiae was preferred to lay more eggs host pupae with small size, however, more females of offsprings were produ~~ed from larger host pupae. The development time and longevity of female and male offsprings maintained constant regardless of host size. The results suggested that B. dorsalis could allocate its offspring number and sex ratio, so as to maximize its fitness, based on assessment of host pupa mass.