Dung resource identity and diel period jointly structure Scarabaeinae dung beetle assemblages in an agricultural mosaic of the Western Ghats biodiversity hotspot, India

Dung beetles (Coleoptera: Scarabaeinae) are key drivers of nutrient cycling and ecosystem functioning in tropical landscapes, yet how dung resource identity and diel activity period jointly shape their assemblages in agricultural mosaics remains poorly understood. We sampled dung beetles using baited pitfall traps across four dung types – Asian elephant, domestic buffalo, goat, and pig – in paired diurnal and nocturnal exposures in an agricultural landscape of central Kerala, within the Western Ghats biodiversity hotspot. A total of 2791 individuals of 22 species were recorded, comprising exclusively tunnellers and dwellers; no rollers were found. Assemblage composition differed significantly by both dung type and diel period. Diel period was the dominant structuring force, with nocturnal assemblages yielding 8–14 times greater abundance than diurnal ones. Zeta diversity indicated that elephant dung sustained stable core communities, whereas pig dung exhibited rapid species turnover. These findings highlight the importance of conserving diverse dung resources and structurally complex agricultural mosaics for sustaining terrestrial biodiversity and ecosystem services.