Capture efficiency of sampling methods and their effects on the dung beetle (Coleoptera: Scarabaeinae) community in an urban remnant of Amazonian forest

Traps are widely used to collect insects in tropical ecosystems, but the choice of sampling methods has a direct influence on community patterns. Our study aimed to evaluate the efficiency of two methods (pitfall and flight interception trap, FIT) for dung beetle sampling (Coleoptera: Scarabaeinae) in an urban forest area in the Amazon. The traps were installed in four locations and sampled in the hydrological periods of drought and rain in the Utinga State Park, an urban Amazonian protected area. A total of 2192 beetles were captured, distributed in 28 species; 26 species (676 individuals) were recorded in flight interception traps and 20 species (1516 individuals) in pitfall traps. The most abundant species were Canthidium deyrollei (N = 1658), Dichotomius lucasi (N = 199), Dichotomius boreus (N = 147), and Canthon subhyalinus (N = 85). Although fewer individuals were captured in FITs, they recorded more species than pitfall traps. Additionally, FITs exhibited greater efficiency with a sampling effort of 8.2 human hours compared to pitfall traps. Furthermore, the composition was different between the two types of traps. Our results indicate that the selection of collection methodology can be driven by the ecological questions regarding biodiversity in accordance with the study objectives. However, we highlight that better ecological sampling would be done using both methods combined to capture complementary ecosystem functions promoted by dung beetles. Our study highlights that dung beetle collection methodologies are crucial factors to be considered in tropical forest monitoring and conservation projects, especially in urbanized areas.