Natural enemy fauna (Insecta, Araneae) found on native sagebrush steppe plants in eastern Washington with reference to species also found in adjacent apple and pear orchards

Abstract

Seven native plants (four shrubs, two perennial herbs, and a woody vine) common in sagebrush steppe habitats of eastern Washington were sampled for predatory and parasitic arthropods. Sagebrush steppe is a common natural habitat adjacent to apple and pear orchards in that part of the state. Many predatory arthropod species found on the native plants also occur in adjacent orchards; some of these species were particularly abundant on the plants when they were flowering. Other species found on the native plants rarely occur in adjacent orchards. Orius tristicolor (White, 1879) was the most abundant of the natural enemies that also occur in orchards. Other predatory Hemiptera also found in adjacent orchards included Deraeocoris brevis (Uhler, 1904), Nabis alternatus Parshley, 1922, and Geocoris spp. Coccinellidae, Chrysopidae, and Hemerobiidae were not common on the native plants, but one or more species in each family that commonly occur in orchards were collected. Spiders found on the native plants that al...