title: Soybean cyst nematode effects on soybean aphid preference and performance in the laboratory.
abstract: Herbivores on plants frequently interact via shared resources. Studies that have examined performance of herbivores in the presence of other herbivores, however, have often focused on above-ground feeding guilds and relatively less research has examined interactions between below- and  above-ground consumers. We examine how soybean aphid, Aphis glycines (Matsumura) an above-ground phloem-feeding herbivore, interacts with a below-ground plant parasite, soybean cyst nematode, Heterodera glycines (Ichinohe) through their shared host plant, soybean (Glycine max L). Laboratory  experiments evaluated the preference of alate (flight-capable) soybean aphids toward plants either infected with soybean cyst nematode or uninfected controls in a simple choice arena. Alate soybean aphids preferred uninfected soybean over soybean cyst nematode-infected plants: 48 h after the  releases of alate aphids in the center of the arena, 67% more aphids were found on control soybean compared with nematode infected plants. No-choice feeding assays were also conducted using clip cages and apterous (flight-incapable) aphids to investigate effect of soybean cyst nematode infection  of soybean on aphid performance. These studies had mixed results: in one set of experiments overall aphid population growth at 7 d was not statistically different between control and soybean cyst nematode-infected plants. A different experiment using a life-table analysis found that apterous  aphids feeding on soybean cyst nematode-infected plants had significantly greater finite rate of increase (λ), intrinsic rate of increase (r(m)), and net reproductive rate (R(o)) compared with aphids reared on uninfected (control) soybean plants. We conclude that the  below-ground herbivore, soybean cyst nematode, primarily influences soybean aphid behavior rather than performance.
authors.affiliation: Department of Entomology, University of Wisconsin/Madison, 237 Russell Labs, 1630 Linden Drive, Madison, WI 53706, USA.
authors.forename: S C
authors.initials: SC
authors.lastname: Hong
authors.forename: J
authors.initials: J
authors.lastname: Donaldson
authors.forename: C
authors.initials: C
authors.lastname: Gratton
mesh_terms: D000818:Animals; D001042:Aphids / Q000254:growth & development / Q000502:physiology*; D005260:Female; D005518:Food Preferences; D060434:Herbivory; D015993:Life Tables; D010935:Plant Diseases / Q000469:parasitology; D018517:Plant Roots; D011156:Population Density; D013025:Glycine max / Q000254:growth & development / Q000469:parasitology*; D014431:Tylenchoidea / Q000254:growth & development / Q000502:physiology*