Submitted to: Journal of Entomological Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/30/2017
Publication Date: N/A
Citation: N/A Interpretive Summary: Urban residents and home-builders can choose native or non-native woody plants when vegetating their properties. However, the effect of these choices on biological control of insect pests has not been studied. We reason that biological control will be more effective in landscapes composed of native plants because native natural enemies of pests have evolved for millions of years with native plants, and are therefore better able to use the resources native plants provide to them than they are to use those provided by exotic plants with which they have no recent evolutionary history. To test this hypothesis we performed an experiment in which simulated backyards were created by planting either native, or very closely related exotic, woody plants, along with turf, in residential size plots. Insects of one important class of natural enemies, parasitic micro-wasps, were significantly more abundant in the turf of native than of exotic plots, which supports the hypothesis. These results will be of interest to scientists, pest management specialists, home owners, builders, and urban planners.
Technical Abstract: Urban ornamental landscapes tend to be mosaics of native and exotic plants. Although there has been renewed interest in effect of the provenance of plants in the landscape on animals inhabiting them, little attention has been paid to arthropod natural enemies and their hosts. In eastern North America, commonly grown exotic woody plants had been missing from the continent for between from one and tens of millions of years. We present the hypothesis that due to the lack of a recent co-evolutionary history with these plants, native natural enemies will be less well able to utilize the resources – architecture and nutritional supplements – provided by exotic plants than they will those of native plants, hence less numerous and diverse in landscapes dominated by exotic plants. We test this hypothesis in a replicated experiment comprising 0.2 Ha plots planted to congeners of 15 genera of woody plants from either Eurasia or North America, grown in a turf of tall fescue. Adult hymenopterous parasitoids collected by vacuum sampling from the turf were statistically less abundant in the exotic plots, supporting the hypothesis.