Heads or tails? Dung beetle (Coleoptera: Scarabaeidae: Scarabaeinae and Aphodiinae) attraction to carrion

Necrophilous insects occupy an ecologically interesting niche because carrion is a highly desirable but ephemeral food source. Dung beetles (Coleoptera: Scarabaeidae: Scarabaeinae and Aphodiinae) within temperate regions are frequently found at carrion, but little is known about their attraction to this resource. Are dung beetles attracted to the carrion itself or are they indirectly attracted due to the exposed gastrointestinal contents? We investigated the association between dung beetles and carrion by examining the distribution of dung beetles on the cranial and caudal end of rat carcasses, delimiting a resource more attractive to necrophagous insects (cranial end) from a resource more attractive to coprophagous insects (caudal end). Dung beetle distribution on rat carcasses was compared with the distribution of carrion beetles (Coleoptera: Silphidae), which serve as a null model of distribution patterns for a taxon known to directly target carrion. Results demonstrated that dung beetles show higher attraction to the cranial end of rat carrion. A similar distribution pattern was found in carrion beetles, suggesting that similar resources were targeted. When dung beetles were grouped by behavioral guilds, rollers and tunnelers also shared this pattern of greater abundance at the cranial end, but dwellers showed no discernible difference.