Submitted to: American Entomologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/27/2005
Publication Date: 12/15/2005
Citation: Ellsbury, M.M., French, B.W., Noble, C.W., Head, G., Fuller, B.W., Pikul Jr, J.L. Winter 2005. Variation in spatial distribution and diurnal activity cycles of ground beetles (Coleoptera: Carabidae) encountered in experimental settings for study of sustainability issues. American Entomologist. 51(4):219-223. Interpretive Summary: Scientific study is often done with the goal of determining the feasibility, benefits, or even possible detriments resulting from changes or proposed improvements in crop production practices. Such research by definition attempts to maintain all outside influences constant except for the one factor or procedure being measured. This article explores the reasons why this goal is often very difficult to achieve. The article uses two scientific studies of ground beetles as examples. In both studies ground beetles are used because their numbers often change in response to changes in their environment.
Technical Abstract: Ground beetles (Coleoptera: Carabidae) are of particular interest in agroecosystems because they are effective predators of soil and canopy-dwelling pests and also are considered positive indicators of sustainability. Harvest of corn stover for biofuels production and inversion tillage practices may result in reduced surface residue and, consequently, in lower activity of beneficial arthropods. Likewise there is concern that ground beetles may be adversely affected by plant-incorporated insecticides targeted for corn rootworm. In a series of field experiments, we tested hypotheses that ground beetles, as indicator species, are unaffected by the various management practices in questions. Variation in diurnal activity cycles was documented from time-sort pitfall trapping in tillage and stover removal studies. Crop-specific spatial distributions and influence of topography on beetle spatial distributions were apparent in a georeferenced grid array of pitfall traps in studies of ground beetles in replicated plots of plant-incorporated insecticides in genetically-modified corn.