The structure of epigeic beetle (Coleoptera) assemblages in Arctic Canada

Seasonal patterns in the structure of epigeic Coleoptera assemblages in two habitats were studied in Kugluktuk, Nunavut. Using pan and pitfall traps, 2638 beetles were collected between June and August 2010. Fifty species (including 17 new territory records) in 11 families were identified. The biomass of each specimen was estimated, and each was assigned to a functional group based on predominant mode of feeding. The assemblages in the two habitats were distinct, and both experienced seasonal turnover in function. Both habitats were dominated by an entomophagous fauna, indicating an “inverse trophic pyramid”; this trophic structure is currently under investigation. We also examined the influence of seasonal weather patterns on assemblage structure: there is a significant relationship between mean daily temperature and functional structure throughout the active season. This relationship indicates that changes in weather (or longer-term changes in climate) could affect the provision of ecological functions by insects. Given the significance of insects in the north, this could result in important changes to Arctic ecosystems.