寄主种类、距离和种群密度对烟粉虱扩散的影响

在笼罩条件下,分别以黄瓜、棉花、蕹菜为虫源寄主和诱集寄主,研究寄主植物、空间距离、虫源密度等因子对B型烟粉虱扩散的影响。结果发现,从虫源寄主上扩散的成虫量,与烟粉虱对诱集寄主和虫源寄主的嗜性差异程度有关,诱集寄主相对于虫源寄主的嗜性越强,扩散出来的成虫数量就越多,反之扩散的成虫数量就越少。成虫扩散量与诱集寄主的距离呈负相关,并且诱集寄主的嗜性越强,随着距离的增大,诱集量下降的速率越快。成虫扩散量与虫源种群密度呈正关,但非嗜好寄主上的虫口承载量相对较低,在虫口密度相对较高时,非嗜好寄主上烟粉虱向外扩散的相对量更大。烟粉虱的扩散量与寄主营养状况呈负相关,寄主营养胁迫时,非嗜好寄主上可以获得相对更高的诱集量。

Effect of host species, host distance and population density on dispersal activity of Bemisia tabaci

The sweetpotato whitefly(Bemisia tabaci biotype "B") is able to disperse among various host-plants.This whitefly's dispersal activity among three host species,including cucumber,cotton and water spinach,was investigated in the laboratory,where one of these host species with whiteflies was served as a source host while all the three host species without whiteflies were used as trap hosts.The number of adult whiteflies dispersed to different trap hosts was positively correlated to the host preference levels and negatively correlated to the distance between the two hosts.The number of adults moved to a new host was positively correlated to the population density on the source host.The ratio of adults dispersed from less preferred hosts was higher than that from preferred hosts when the population density on the source host was relatively high.The number of adults dispersed was negatively correlated to host nutrition levels.Whitefly migration in an ecosystem was discussed.