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双斑恩蚜小蜂和桨角蚜小蜂是华南地区烟粉虱的两种优势种寄生蜂。本文研究了两种寄生蜂对不同龄期烟粉虱寄主的产卵选择特性。结果表明:两种寄生蜂均可寄生烟粉虱的1~4龄若虫。当只有1个龄期的烟粉虱若虫存在时,双斑恩蚜小蜂更多地寄生3龄和4龄若虫,较少寄生1龄和2龄若虫;而桨角蚜小蜂则更多地寄生3龄和2龄若虫,较少寄生1龄和4龄若虫。在4个龄期若虫同时存在时,双斑恩蚜小蜂会明显增加对3龄和4龄若虫的产卵寄生,降低对1龄和2龄若虫的寄生;而桨角蚜小蜂则增加对2龄和3龄若虫的寄生,减少对1龄和4龄若虫的寄生。寄主植物的差异不影响这二种蚜小蜂对各龄期烟粉虱若虫的产卵选择倾向。结果提示,烟粉虱若虫3龄和4龄是双斑恩蚜小蜂最适宜的寄主,而桨角蚜小蜂最适宜的寄主是烟粉虱2龄和3龄若虫。
Bifidus aphid Bumblebee and the Aphis gossypii were two dominant parasitoids of Bemisia tabaci in southern China. In this paper, we studied the spawning characteristics of two parasitoids on B. tabaci hosts at different ages. The results showed that both parasitic wasps could parasitize the 1st to 4th instar nymphs of B. tabaci. When only one age-stage B. tabaci nymphs were present, the B. bifidum bee parasitized more 3rd and 4th instar nymphs, less parasitic 1st and 2nd instar nymphs, and more Parasitic 3rd and 2nd instar nymphs, less parasitic 1st and 4th instar nymphs. At 4 instar nymphs, the Baphicanthus avenae larvae significantly increased spawning parasitism of 3rd and 4th instar nymphs and decreased the parasitism of 1st and 2nd instar nymphs; while the Aphis gossypii increased Parasitism of 2nd and 3rd instar nymphs reduces parasitism of 1st and 4th instar nymphs. The difference of host plants did not affect the tendency of the two kinds of aphid larvae to lay oviposit on whitefly nymphs of different stages. The results showed that the 3rd and 4th instar nymphs of B. tabaci were the most suitable host for B. tabaci, and the most suitable host for B. tabaci was 2nd and 3rd instar nymphs of B. tabaci.