褐带蚜小蜂成虫生物学特性

【目的】褐带蚜小蜂Aphelinus maculatus是近几年发现的棉蚜Aphis gossypii重要寄生蜂之一。目前关于该寄生蜂生物学特性包括行为习性方面的研究非常少。为有效挖掘利用褐带蚜小蜂，对其成虫生物学特性进行了研究。【方法】在室内采取体视显微镜下观察和记录褐带蚜小蜂的羽化节律、交配行为、交配各阶段持续时间、交配次数、交配竞争、不同生殖方式下所产子代性比以及成虫寿命，并观察其对棉蚜若蚜的寄生过程、在棉蚜若蚜上寄生和取食时产卵器的刺入时间以及对不同日龄棉蚜若蚜的寄生和取食选择。【结果】褐带蚜小蜂羽化时间集中在上午6∶00-10∶00。羽化当天即可交配，交配过程可分为求偶、交配前期、交配及交配后期4个阶段，交配时间短，平均为5.5±0.2 s。1头雄蜂可与2~4头雌蜂交配，但雌蜂在所观察时间内只交配1次。雌蜂和雄蜂都存在交配竞争现象。褐带蚜小蜂可进行孤雌生殖和两性生殖，孤雌生殖的子代均为雄性，两性生殖的子代雌、雄兼有。产卵寄生过程可划分为寻找寄主、试探寄主、刺探寄主、产卵寄生或取食寄主及清扫梳理这些步骤。产卵寄生或取食寄主的决策与产卵器刺入时间长短有关，刺入时间大于4.8 min时，多会决策取食寄主。褐带蚜小蜂成蜂喜欢取食棉蚜低龄若蚜，很少取食4或5日龄若蚜；但可寄生棉蚜各日龄若蚜。一头雌蜂在24 h内平均可寄生14.8头棉蚜若蚜，取食3.7头棉蚜若蚜。褐带蚜小蜂成虫寿命与羽化后补充营养有关，取食10%蔗糖和10%蜂蜜水的成虫寿命均显著延长，其寿命分别为24±2.5和28±1.6 d。【结论】褐带蚜小蜂可进行孤雌生殖和两性生殖，雌蜂个体间及雄蜂个体间均存在交配竞争。该蜂是卵育型蚜虫内寄生蜂，可取食蚜虫，提供糖蜜可延长其成蜂寿命。

Biological characteristics of adultAphelinus maculatus(Hymenoptera: Aphelinidae)

【Aim】 Aphelinus maculatus is one of the important parasitic wasps parasitizing on the cotton aphid, Aphis gossypii, discovered in recent years. There is little study on the biological characteristics including behavior and habits of Ap. maculatus so far. In order to explore and utilize this wasp effectively, it is important to ascertain its biological characteristics. 【Methods】 The emergence rhythm, mating behaviors, duration of various stages of mating, mating frequency, mating competition, sex ratio of offsprings reproduced by different reproductive modes, and longevity of adult Ap. maculatus were observed and recorded under microscope in the laboratory, and the parasitization process of this parasitoid on A. gossypii nymphs, the ovipositor insertion time of Ap. maculatus adults when parasitizing and feeding on A. gossypii, and the parasitization and feeding selection of Ap. maculatus adults to different day-old nympyhs of A. gossypii were also observed. 【Results】 Ap. maculatus adults emerge mainly at 6∶00-10∶00 am. Female and male adults mate on the day of emergence. The mating process can be divided into four phases: courtship, precopulation, copulation and postcopulation. The copulation duration is short, only lasting for 5.5±0.2 s. One male can copulate with 2-4 unmated females within 3 h, while the female only copulate once. Mating competition occurs among females and also among males. Ap. maculatus can reproduce offspring by parthenogenesis and amphigenesis. Only male offsprings are reproduced by parthenogenesis, but both female and male offsprings by amphigenesis. The parasitization process can be divided into such steps as searching host, examining host, probing insertion site, parasitic oviposition or feeding host, and cleaning and carding. The decision of parasitic oviposition or host feeding is related to the ovipositor insertion time into aphid body. When the ovipositor insertion time is longer than 4.8 min, adult wasps are more likely to feed host. Ap. maculatus wasps prefer to feed the early instar nymphs of A. gossypii, rarely feed 4 d or 5 d old nymphs, but can parasitize different day old nymphs of A. gossypii. One female wasp can parasitize 14.8 A. gossypii nymphs and feed 3.7 A. gossypii nymphs on the average within 24 h. The adult longevity of Ap. maculatus is related to nutrient supplement after adult emergence. Adult wasps fed 10% sucrose and 10% honey could live 24±2.5 d and 28±1.6 d, respectively. 【Conclusion】 Ap. maculatus can reproduce by parthenogenesis and amphigenesis. Mating competition occurs among both females and males. The adult longevity of Ap. maculatus can be prolonged by supplying sucrose or honey.