Ground Beetles (Coleoptera: Carabidae) in Relation to Agricultural Crops

Abstract

AbstractA three-year study on the seasonal occurrence of ground beetles was conducted in five fields with different crop rotations. More than 10,000 individuals representing 102 species were captured in pitfall traps. The relatively high total number of species collected the first year probably resulted from the particular location of the traps along field margins and close to woodlands. The variation observed between the areas studied was not necessarily related to the kind of crop. A progressive augmentation in beetle activity and population appeared to coincide with an increase in the humidity of the habitats and with the cultures in the following order: pasture grass, forage, cultivated, and cereal crops. This indicates that the nature of the crop influences beetle numbers, and from this it may he inferred that it also influences the extent to which the beetles exert a control influence on pest species. Of the eight species present every year and found in practically every field, Pterostichus melanarius Ill., Harpalus pennsylvanicus DeG., and H. compar Lec. were the most numerous.