Weed seed predation in arable field margins by carabid beetles (Carabidae: Coleoptera).

Abstract

An experiment was designed to compare weed seed consumption in winter wheat fields by Carabid beetles at the field boundary and within a field. Petri dishes containing a mixture of Avena fatua, Alopecurus myosuroides, Polygonum persicaria, Viola arvensis, Stellaria media and Chenopodium album were placed 0 m and 40 m from the field boundary. Half the dishes were enclosed in a mesh cage, which excluded all predators except carabid beetles. Dishes were collected at two-weekly intervals and the number of remaining seeds counted. Seed predation was found to be highly variable through time and between sites. No significant difference was found between dishes at 0 and 40 m from the field boundary. However significant levels of seed loss were obtained from dishes enclosed within cages compared with those accessible to all predators.