Dog Waste Creates a Preference-Performance Mismatch for Urban Dung Beetles

Urban environments expose animals to novel conditions that may favor behavioral flexibility but can create preference-performance mismatches when attractive resources are associated with reduced reproductive success. Dung beetles are often considered dietary generalists, yet little is known about how they respond to altered food availability in human-dominated habitats. We combined field surveys and laboratory experiments using two domestic dung types to examine diet preference, maternal provisioning, and offspring performance in the urban dung beetle Onthophagus orpheus. Beetles strongly preferred dog dung over cow dung, and offspring reared on dog dung developed faster and emerged as larger adults. Despite these apparent benefits, brood ball mortality was more than twice as high on dog dung, with nearly 60% of brood balls failing compared to only 25% on cow dung. Thus, the dung type most strongly preferred by adults was also associated with the lowest offspring survival. This preference-performance mismatch suggests that accumulation of domestic dog waste-a pervasive feature of urban habitats-may pose a widespread but underappreciated risk to urban dung beetles.