Spatial Dynamics of Host/Parasitoid Interactions: Indirect Effects of Aphids

点击翻译按钮获取中文摘要

Indirect interactions among organisms are emerging as widespread, important factors in many ecological communities. This research tests the general hypothesis that phytophagous insects interact indirectly through strong effects on the spatial dynamics of natural enemy activity. In particular, it assesses whether aphids (typically among the most abundant and widespread of all phytophagous insects in temperate ecosystems) influence spatial variation in the intensity of parasitism of other insects; parasitoids may accumulate in local areas, and increase their longevity and fecundity, by consuming aphid honeydew. Insect communities of alfalfa provide an excellent test system. Field experiments in alfalfa will test for indirect effects of pea aphids on the alfalfa weevil, as mediated by a parasite wasp specific to the weevil, and as influenced by natural enemies of the pea aphid (ladybeetles). Investigating the web of indirect as well as direct interactions in alfalfa insect communities provides opportunity not only to test for processes of general ecological interest, but also to contribute to more effective management of alfalfa insect pests.