桑天牛卵长尾啮小蜂的寄主选择定位行为

本文对桑天牛卵长尾啮小蜂Aprostocetus prolixus LaSalle et Huang的寄主选择定位行为进行了系统研究。已有研究表明，寄主植物-寄主昆虫复合体释放的挥发物对寄生蜂有显著的引诱作用。为了查明寄主植物 寄主昆虫复合体中挥发性引诱物质的来源，对不同处理桑枝（正常桑枝、机械损伤桑枝、系统枝、桑天牛Apriona germari（Hope）咬食和产卵桑枝）、桑天牛虫粪及雌雄两性桑天牛所释放的挥发物分别进行了测定。结果显示：不同处理桑枝对寄生蜂都具有显著的引诱作用，而且产卵桑枝的引诱活性最大；桑天牛虫粪的气味对寄生蜂有引诱活性，而雌、雄桑天牛体表挥发物对寄生蜂的引诱效果不明显。桑天牛爬行痕迹对寄生蜂的微栖境接受行为没有影响，而桑天牛虫粪中的信息物质在寄生蜂的微栖境接受过程中起着重要作用。寄生蜂对产卵桑枝段的选择几率明显高于正常桑枝段和咬食桑枝段，而对不同植物上产卵刻槽的选择没有差异； 刻槽表面存在着与此卵寄生蜂寄主识别相关的信息物质。

Host selection and location behavior of Aprostocetus prolixus LaSalle et Huang (Hymenoptera: Eulophidae), an egg parasitoid of Apriona germari (Hope) ( Coleoptera: Cerambycidae)

In this paper, the host selection and location behavior of Aprostocetus prolixus lasalle et Huang was investigated systemically. Many studies showed that volatiles of host plant-insect complex could attract the parasitoid. In order to determine the source of the attractive volatiles within the host plant-insect complex, we examined separately the volatiles that Morus alba twigs with different treatments (healthy twigs, mechanically damaged twigs, system twigs, and twigs infested either by feeding or by oviposition of Apriona germari), faeces of A. germari, and both sexes of the host insect A. germari. The results revealed that the twigs in all treatments attracted the wasp significantly. In addition, the volatiles from egg-laid twigs were the most attractive compared with those from other differently treated twigs. Odours from faeces of host insect elicited a positive response of A. prolixus, but volatiles neither from male nor from female host insect acted as attractants. The effect of A. germari walking traces on microhabitat acceptance behavior of the wasp was not found in open arena assays, whereas the kairomones from feaces of A. germari were demonstrated to be important in the process of microhabitat acceptance for parasitoids by Petri dish bioassays. In choice tests, A. prolixus preferred egg-deposited M. alba twig to healthy or feeding-damaged twig, but the significant differences in the choice of host units among different host plants were not detected. There were infochemicals involved in host recognition by the egg parasitiod on the surface of host-unit.