The ‘hidden’ rove beetle (Coleoptera: Staphylinidae) assemblage of soybean agroecosystems: Diversity, activity patterns and species of interest to pest management

Previous North American surveys of natural enemy assemblages in soybean have reported rove beetles (Staphylinidae) as absent or rare. The abundance and diversity of Staphylinidae in other terrestrial ecosystems, including agroecosystems suggests that their role in soybean assemblages needs reinvestigation. Soybean fields and their adjacent hedgerows (outside of the growing season) in Ontario, Canada were sampled biweekly in 2009 and 2010, using pitfall and canopy traps. Suction sampling in soybean fields, conducted in 2009 over two 48-hour periods, determined rove beetle foliar activity to peak from 8-12pm. Species poorly sampled by pitfall traps were effectively sampled using suctioning. Sixty-two species comprised the staphylinid assemblage in soybean, with Aleocharinae as the most dominant subfamily; Strigota n. sp. represented 45% of all individuals captured. The staphylinid assemblage in soybean consisted primarily of eurytopic or open-ground species that were present over the entire growing season; more than half the abundant species were exotic in North America. All species abundant in soybean fields were found to inhabit hedgerows in spring and/or fall, suggesting that these areas support relevant rove beetle populations outside of the growing season. Drawing upon known biology and co-incidence with pest seasonality and microhabitat, several common species are suggested for future investigation of their role in management of important soybean pests.