Ground arthropod communities in paddy fields during the dry period: Comparison between different farming methods

Abstract

The ground arthropod communities in paddy fields during the dry period and the effects of different farming methods adopted during the cropping season on these communities were evaluated. Pitfall traps were used in six conventional, two herbicide-only, and four organic paddy fields in early November and early May at two sites in Niigata Prefecture, Japan. A total of 202 ground arthropods belonging to 18 taxa were collected, with eight taxa identified at the species level. The most abundant taxa were two predator groups, spiders and carabid beetles. Farming methods did not affect taxon richness, total abundance, abundance of individual taxa, or species composition, but the site marginally affected the abundance of some taxa. These results suggest that during the dry period paddy fields contained abundant predatory arthropods, and that the communities were not affected by the use of pesticides during the cultivation period. Because these predators are important natural enemies of rice pests, management strategies should be focused on both the cultivation period and the uncropped, dry period to enhance predator populations.