Agricultural pest suppression is an important ecosystem service that may be threatened by the loss of predator diversity. This has stimulated interest in the relationship between predator biodiversity and biological control. Multiple-predator studies have shown that predators may complement or interfere with one another, but few experiments have determined if the resulting effects on prey are c...

In surveys of apple-production areas east of the Cascade Mountains of Washington, broadleaf plantain, Plantago major Linnaeus (Plantaginaceae) was common throughout while narrowleaf plantain, P. lanceolata Linnaeus, was most common south of Orondo, Douglas County (47.7u latitude). Rosy apple aphid was the most common aphid on these two herbaceous plants; however, colonies were scarce, on only 1...

Positive species interactions have the potential to strongly influence the structure and dynamics of ecological communities, yet surprisingly few studies have documented their general importance. We tested the hypothesis that the mutualistic association between fire ants and aphids enhances the impact of fire ants on the herbivorous and predaceous arthropod community of cotton. We found that th...

Coexistence of host-specific herbivores on plants is believed to be governed by interspecific interactions, but few empirical studies have systematically unraveled these dynamics. We investigated the role of several factors in promoting coexistence among the aphids Aphis nerii, Aphis asclepiadis, and Myzocallis asclepiadis that all specialize on common milkweed (Asclepias syriaca). Competitive ...

Genetic variation in plants is known to influence arthropod assemblages and species interactions. However, these influences may be contingent upon local environmental conditions. Here, we examine how plant genotype-based trophic interactions and patterns of natural selection change across environments. Studying the cottonwood tree, Populus angustifolia, the galling aphid, Pemphigus betae and it...

A granulosis virus was tested as a potential control agent for codling moth larvae on walnuts. The virus was produced and supplied by Sandoz, Inc. as our experimental insecticide. This virus is of considerable interest because it has little or no effect on beneficial parasites and predators and, therefore, probably would not disturb the control of the walnut aphid by the parasite Trioxys palladus.

Red imported Þre ants, Solenopsis invicta (Buren) (Hymenoptera: Formicidae), are an invasive species found in high densities throughout southeastern agricultural systems. We tested the hypothesis that Þre ants tend cotton aphids, Aphis gossypiiGlover (Homoptera: Aphididae), and thus release them from predation by lady beetle larvae, Coccinella septempunctata L. and Hippodamia convergens Guerin-...

a two-year field study was conducted at punjab agricultural university, ludhiana, india, to study the relative abundance of mustard/turnip aphid, lipaphis erysimi (kaltenbach) (hemiptera: aphididae) and the associated resident natural enemies on 10 different rapeseed-mustard genotypes which included: brassica juncea: rh 7846, rh 9501, rk 9501, jmm 927, purple mutant; b. napus: hyola pac 401 (hy...

Aphid predators are a systematically disparate group of arthropods united on the basis that they consume aphids as part of their diet. In Europe, this group includes Araneae, Opiliones, Heteroptera, chrysopids, Forficulina, syrphid larvae, carabids, staphylinids, cantharids and coccinellids. This functional group has no phylogenetic meaning but was created by ecologists as a way of understandin...

Mechanisms that allow for the coexistence of two competing species that share a trophic level can be broadly divided into those that prevent competitive exclusion of one species within a local area, and those that allow for coexistence only at a regional level. While the presence of aphid-tending ants can change the distribution of aphids among host plants, the role of mutualistic ants has not ...