Abundance and Diversity of Adult Carabidae in Insecticide-Treated and Untreated Alfalfa Fields

Los, Lorraine; Allen, William A.

doi:10.1093/ee/12.4.1068

Cited by 19 publications

(7 citation statements)

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“…Many studies have documented negative effects of insecticides on nontarget invertebrates, including decreases in species richness or abundance of important predators, such as carabids (Los andAllen 1983, Teodorescu &Cogalniceanu 2005). Duan et al (2004) compared transgenic and nontransgenic potato management on nontarget communities and found a signiÞcant decrease in spider abundance caused by permethrin but not transgenic management.…”

Section: Discussionmentioning

confidence: 99%

Transgenes Sustain Epigeal Insect Biodiversity in Diversified Vegetable Farm Systems

Leslie

Hoheisel

Biddinger

et al. 2007

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Many ecological studies have focused on the effects of transgenes in Þeld crops, but few have considered multiple transgenes in diversiÞed vegetable systems. We compared the epigeal, or soil surface-dwelling, communities of Coleoptera and Formicidae between transgenic and isoline vegetable systems consisting of sweet corn, potato, and acorn squash, with transgenic cultivars expressing Cry1(A)b, Cry3, or viral coat proteins. Vegetables were grown in replicated split plots over 2 yr with integrated pest management (IPM) standards deÞning insecticide use patterns. More than 77.6% of 11,925 insects from 1,512 pitfall traps were identiÞed to species, and activity density was used to compare dominance distribution, species richness, and community composition. Measures of epigeal biodiversity were always equal in transgenic vegetables, which required fewer insecticide applications than their near isolines. There were no differences in species richness between transgenic and isoline treatments at the farm system and individual crop level. Dominance distributions were also similar between transgenic and isoline farming systems. Crop type, and not genotype, had a signiÞcant inßuence on Carabidae and Staphylinidae community composition in the Þrst year, but there were no treatment effects in the second year, possibly because of homogenizing effects of crop rotations. Communities were more inßuenced by crop type, and possibly crop rotation, than by genotype. The heterogeneity of crops and rotations in diversiÞed vegetable farms seems to aid in preserving epigeal biodiversity, which may be supplemented by reductions in insecticide use associated with transgenic cultivars.

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Section: Discussionmentioning

confidence: 99%

Transgenes Sustain Epigeal Insect Biodiversity in Diversified Vegetable Farm Systems

Leslie

Hoheisel

Biddinger

et al. 2007

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“…The contribution of ground-foraging predators to pest suppression is particularly interesting because it is highly variable and can potentially be manipulated. The density of ground-foraging predators is known to be affected by both plant diversity and the use of insecticides (Los and Allen 1983, Barney et al 1984, Barney and Pass 1986. Predictions of the temporal and spatial patterns of ground-foraging predators in relation to the period of pest susceptibility could be used as a guide for choosing systems for focusing efforts on conserving or even augmenting ground-foraging predators.…”

Section: Discussionmentioning

confidence: 99%

Factors Facilitating Synergistic Predation: The Central Role of Synchrony

Losey

Denno

1999

Ecological Applications

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Determining the phenological and diel concurrence of potentially overlapping predator guilds in a given system provides a gauge of the potential prevalence and importance of synergistic prey suppression. The phenology of pea aphids (Acyrthosiphon pisum) and ground‐ and foliar‐foraging predators was determined through a combination of pitfall and sweep‐net sampling in alfalfa. These results revealed diverse guilds of ground‐ and foliar‐foraging predators with a high degree of phenological overlap among individual species. One of the most common ground‐foraging predators, Harpalus pennsylvanicus, was found to be significantly more active at night, but also to maintain moderate activity levels during the day. When tested individually in simple arenas with full access to aphids, the aphid‐consumption rates of five common ground‐foraging predators (H. aeneus, H. pennsylvanicus, Amara familiaris, A. octopunctatum, and Philonthus spp.) were not significantly different from that of Coccinella septempunctata, a foliar‐foraging predator that is held to be one of the most important aphid consumers in alfalfa. Thus, both the seasonal occurrence and daily activity levels of these two aphid predator guilds overlap, and the ground‐foraging predators, which are often overlooked as sources of aphid predation, were shown to be effective aphid consumers. Three key elements emerge from the alfalfa–aphid–predator system as general predictors of the probability for the synergistic predation on pests by members of a predator complex: (1) synchrony of predator species in the complex, (2) predator‐induced escape behavior of prey resulting in habitat switching and encounter with a new predator guild, and (3) minimal negative interaction (intraguild predation or interference) between the predator species. These elements can aid in identifying systems where the conservation or augmentation of ground‐foraging predators or other interactive predator guilds will be most effective.

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“…If pea aphids are dislodged from their host plant, they may be at risk from ground-foraging predators. The ground-predator complex in alfalfa is also abundant and diverse (Pimentel & Wheeler, 1973;Yeargan & Dondale, 1974;Frazer et al, 1981;Los & Allen, 1983;Barney et al, 1984). In Maryland, carabid and staphylinid beetles are the most abundant ground-foraging predators (Losey, 1996), a community composition that appears to be representative of alfalfa systems in general (Barney et al, 1984).…”

Section: Ground-foraging Predators In Alfalfamentioning

confidence: 99%

The escape response of pea aphids to foliar‐foraging predators: factors affecting dropping behaviour

Losey

Denno

1998

Ecological Entomology

210

182

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1. The effects of predator species, aphid density, aphid age, diel period, and habitat complexity on the dropping behaviour of the pea aphid Acyrthosiphon pisum were assessed in a series of laboratory and field-cage experiments.2. The presence of foliar-foraging predators significantly increased the proportion of aphids that dropped from alfalfa plants. In the absence of predators, less than 7% of the aphids dropped. Dropping more than doubled (14%) when one of three hemipteran predators, N. americoferus, G. punctipes or O. insidiosus, was present. Nearly 60% of the aphids dropped when the ladybird beetle, Coccinella septempunctata, was present.3. Adult aphids showed a significantly higher propensity to drop than immature aphids, regardless of the presence or absence of predators. Aphid density had no effect on dropping behaviour. 4. Neither diel period nor habitat complexity had an effect on aphid dropping behaviour. Aphids were significantly more likely to drop in the presence of predators during either the day or night and from either early or late regrowth alfalfa. 5. A review of the factors affecting dropping behaviour, including those elucidated in this study, indicates that the propensity to drop from a plant is influenced by three factors: the risk of predation on the plant, the quality of the resource to be abandoned, and the risk of mortality in the new microhabitat.

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Abundance and Diversity of Adult Carabidae in Insecticide-Treated and Untreated Alfalfa Fields

Cited by 19 publications

References 0 publications

Transgenes Sustain Epigeal Insect Biodiversity in Diversified Vegetable Farm Systems

Transgenes Sustain Epigeal Insect Biodiversity in Diversified Vegetable Farm Systems

Factors Facilitating Synergistic Predation: The Central Role of Synchrony

The escape response of pea aphids to foliar‐foraging predators: factors affecting dropping behaviour

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