班氏跳小蜂对寄主龄期选择的研究

Host-instar selection of Aenasius bambawalei Hayat(Hymenoptera:Encyrtidae) for mealybug Phenacoccus solenopsis Tinsley(Hemiptera:Pseudococcidae)

班氏跳小蜂Aenasiusbam bawalei Hayat是扶桑绵粉蚧Phenacoccus solenopsis Tinsley的优势种寄生蜂。本文研究了在限制选择和自由选择的条件下,扶桑绵粉蚧的2龄若虫、3龄若虫和雌成虫对该蜂的寄生率、发育历期、子代性比和个体大小的影响。结果表明:在两种选择条件下,班氏跳小蜂对扶桑绵粉蚧3龄若虫的寄生率显著高于对雌成虫和2龄若虫的寄生率,但寄生粉蚧雌成虫的子代雌雄性比显著高于寄生3龄若虫或2龄若虫的性比;在两种选择条件下,雌蜂在寄主三种虫龄(态)上的发育历期差异不显著,但是雄蜂在粉蚧雌成虫中的发育历期显著长于寄生2龄若虫或3龄若虫的发育历期;在两种选择条件下,寄生于粉蚧雌成虫的子代雌蜂和雄蜂的个体都是最大,其后足胫节长度显著长于寄生于2龄若虫或3龄若虫的子代胫节的长度。

The parasitoid, Aenasius bambawalei Hayat, has been recently reported as the predominant natural enemy of the solenopsis mealybug, Phenacoccus solenopsis Tinsley （Hemiptera： Pseudococcidae）. In this study, the 2^nd instar nymph, 3^rd instar nymph and female adults of the mealybug were exposed to A. bambawalei in the free choice and restrictive choice experiments to investigate the effect of the stages on the parasitism, development, sex ratio and body size of the progeny of A. bambawalei. The 3^rd instar nymph of P. solenopsis was the most suitable life stage for oviposition by A. bambawalei in both experiments, while the parasitization of P. solertopsis female adult by A. bambawalei resulted in the highest female ratio of progeny. In both experiments, the three stages had no significant effect on the develop- mental time of female progeny of A. bambawalei; however, the developmental time of male progeny of A. bambawalei from P. solenopsis female adult was longer than that from 2nd and 3rd instars hosts. Progeny of A. bambawalei reared from P. solenopsis female adult are bigger than those from 2nd and 3rd instars nymph in both experiments.