烟粉虱对寄主植物叶背的定向行为

烟粉虱Bemisia tabaci(Gennadius)成虫在自然条件下总是能够准确定位到寄主的叶片背面进行取食和产卵,这是一种本能的定向行为。以扶桑和油麦菜为寄主材料,通过非选择性和选择性实验,研究和评价光照、叶面物理性状和重力3个环境因子在烟粉虱成虫定向行为中的作用。结果显示,重力在定向行为中起主导作用,寄主叶片正反面的物理性状差异也能够使烟粉虱成虫定位到寄主叶片的背面,但是存在时滞效应。说明烟粉虱成虫在定向到寄主叶片背面的过程中存在2个系统,一个是以重力为线索的垂直方向感作为导航系统,另一个则是以叶面物理性状为线索的行为调节作为校正系统,二者的相互协作使得烟粉虱成虫能够精确定位到寄主叶片的背面。

Orientation behavior of Bemisia tabaci to locate underside of host leaves

Bemisia tabaci(Gennadius) has a good ability to land on underside of host leaves for feeding and ovipositing under natural condition.It could be regarded as instinctive behavior.In this case,with selection and non-selection experiments,we studied and evaluated the effect of light,physical features of leaves and gravitation as cues on the whitefly's orientation behavior to locate underside of host leaves.The results show that gravitation plays a dominant role on the process of orientation,and physical features of leaves also enable whitefly to locate underside of leaves with a little delay.It obviously indicates that orientation behaviors of whitefly to locate underside of leaves are consisted of two systems,one of which is navigation system based on vertical direction used gravitation as a cue,and another is revising system based on switched behavior used physical features of host leaves as a cue.Combined with navigation and revising system,whitefly builds a quite accurate orientating system to land on underside of host leaves.