|Elliott, Norman - Norm|
Submitted to: Biocontrol
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/17/2005
Publication Date: 2/1/2006
Citation: Elliott, N.C., Tao, F.L., Giles, K.L., Royer, T.A., Greenstone, M.H., Shufran, K.A. 2006. First quantitative study of rove beetles in Oklahoma winter wheat fields. Biocontrol. 51:79-87. Interpretive Summary: Many rove beetle species (family Staphylinidae) are predators of pest insects in agricultural crops. In Europe, where they have been fairly well studied, rove beetles are part of a complex of predatory arthropods that biologically control cereal aphids in wheat. Very little is known about rove beetles in Oklahoma winter wheat. Our two-year study was done to obtain basic information on the rove beetle species that occur in winter wheat fields in Oklahoma, and how they vary in abundance with respect to factors such as geographic location and the density of cereal aphids. We found 13 species of rove beetle in Oklahoma winter wheat fields. The species of rove beetles in wheat fields varied with season, with some species being present primarily or solely in autumn, winter, or spring, while other species were present in wheat fields throughout the growing season. One species, Tachyporus jocosus Say, was particularly interesting because it was present in all seasons at relatively high density compared to other rove beetle species. Species from the genus Tachyporus have been shown to be particularly important predators of cereal aphids in Europe. This study was a first step, highlighting the fact that soil surface dwelling predatory rove beetles are present in winter wheat fields in Oklahoma, a never before reported observation. Further research will be required to determine the role of these predatory beetles in the biological control of cereal aphids in Oklahoma winter wheat.
Technical Abstract: Rove beetles (Staphylinidae) were sampled every 7 ' 14 d from one winter wheat field located in each of the four major wheat growing regions of Oklahoma during the 1999-2000 and 2000-2001 growing seasons. The sample unit was a 0.5 m**2 circular frame, which was embedded in the soil. Ten samples were taken from each field every 7 ' 14 d throughout each growing season. Sampling was accomplished by suction sampling the area within the frame followed by thorough hand searching. The number of cereal aphids per tiller, wheat plant growth stage, and wheat tiller density also were estimated for the field each time it was sampled. A total of 13 species of rove beetle representing 12 genera were collected from the fields during the two years. The density of rove beetles in the winter wheat fields was generally low, ranging from 0.003 beetles per m**2 in autumn to 0.106 beetles per m**2 in spring. Rove beetle communities differed among seasons. After accounting for the effect of season, there was no statistically significant association between rove beetle community structure (species composition and density) and field location, aphid density, wheat plant growth stage, or wheat plant density. Most rove beetle species showed no strong association with a particular season, however, Aleochara notula Erichson, Lathrobium sp., and Oxypoda sp., were present predominantly in fall, while Bisnius inquitus Erichson was associated with winter. Oxypoda sp. was the most abundant rove beetle in winter wheat fields in spring and was relatively abundant in winter, but was not collected from wheat fields in fall. Tachyporus jocosus Say was present in wheat fields during all seasons. Tachyporus jocosus was the most abundant rove beetle species in the winter wheat fields in fall and winter and was the second most abundant species during spring.