Raymond B, Darby A C, Douglas A E
Department of Biology, University of York, PO Box 373, York, UK, , , , , , GB.
Oecologia. 2000 Aug;124(3):367-372. doi: 10.1007/s004420000396.
An experimental plot of the aphid Aphis fabae on various host plant species was colonized by natural populations of the aphidiine parasitoid Lysiphlebus fabarum and insect predators, especially coccinellids. Parasitism of A. fabae by L. fabarum was significantly depressed on plants bearing coccinellids. The number of parasitized aphids increased with aphid abundance on three plant species (Papaver dubium, Rumex obtusifolius, Vicia faba), but not on the plant species (Chenopodium album) which bore very high numbers of coccinellids. In complementary laboratory experiments, L. fabarum offered a choice between odours of plants infested with A. fabae and/or coccinellids selected the odour fields from coccinellid treatments at significantly lower frequency than the odour fields of other treatments. It is concluded that avoidance of coccinellids by L. fabarum contributes to the negative association between the abundance of coccinellids and parasitoids in the field.
在一个种植多种寄主植物的实验地块上，豆蚜（Aphis fabae）的自然种群被蚜茧蜂（Lysiphlebus fabarum）的自然种群以及昆虫捕食者（尤其是瓢虫）所占据。在有瓢虫的植物上，豆蚜被蚜茧蜂寄生的比例显著降低。在三种植物（野罂粟、钝叶酸模、蚕豆）上，被寄生的蚜虫数量随着蚜虫数量的增加而增加，但在瓢虫数量非常多的藜上则不然。在补充性的实验室实验中，当蚜茧蜂可以在被豆蚜侵染的植物气味和/或瓢虫的气味之间进行选择时，它选择瓢虫处理气味区域的频率显著低于其他处理的气味区域。得出的结论是，蚜茧蜂对瓢虫的回避导致了田间瓢虫和寄生蜂数量之间的负相关关系。
