Submitted to: Environmental Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 26, 1999
Publication Date: N/A
Interpretive Summary: Ground beetles number approximately 40,000 species worldwide, and they eat a variety of agricultural pests. Ground beetles usually disperse into agricultural fields from surrounding natural habitats. Little is known about ground beetles in wheat fields and surrounding riparian strips in Oklahoma. Of 45 species collected in autumn, six species accounted for 64% of the total abundance. Of 36 species collected in winter, six species accounted for 84% of the total abundance. Of 99 species collected in spring, six species accounted for 56% of the total abundance. The occurrence of ground beetles was most strongly influenced by season, followed by year, and then habitat (wheat vs. riparian). Distinct groups of ground beetles were found in autumn, winter, and spring. Based on their capture location, ground beetles were classified as either habitat generalists, wheat specialists, grassland specialists, or edge specialists. .Key species of ground beetles were identified that could potentially assis farmers in the natural control of pest populations in wheat. Riparian strips surrounding wheat fields provide habitats important to the survival of ground beetles.
Technical Abstract: Ground beetles are polyphagous predators of cereal crop pests and are capable of regulating pest populations below economically damaging levels. Ground beetles generally reproduce either in fall or spring and may be habitat generalists or specialists. Ground beetles were captured in spring 1995 at four sites, autumn through spring 1995-1996 at four sites, and autumn through spring 1996-1997 at two sites using pitfall traps positione in riparian strips, wheat fields, and along riparian-wheat field edges. Of 45 species collected in autumn, six species accounted for 64% of the total abundance. Of 36 species collected in winter, six species accounted for 84% of the total abundance. Of 99 species collected in spring, six species accounted for 56% of the total abundance. The numbers of these ground beetles captured varied among years and habitats. Species composition was most strongly related to season, followed by year, and then habitat (wheat vs. riparian strip). Ground beetles that reproduce in spring were separate from those reproducing in autumn along the first axis of a canonical correspondence analysis. With the effects of season and year removed, ground beetles were classified with respect to habitat preference along axes one and two of a partial canonical correspondence analysis. Based on the ordination by partial canonical correspondence analysis, ground beetles were classified as either habitat generalists, wheat specialists, riparian specialists, or boundary specialists. Landscape structure was an important component in determining the spatial distribution of ground beetles.