A Baited Time Sorting Pitfall Trap Allowing More Temporal Fidelity of Dung Beetle (Coleoptera: Scarabaeidae) Activity

Abstract The diel activity of dung beetles is poorly understood in Australia. Understanding diel activity is fundamental to understanding the ecology and management of these insects. The diel activity is typically measured using ground-based pitfall traps, which require manual changing. Here we showcase a time sorting pitfall trap (TSPT) that allows for automated time sorted sampling of dung beetle communities to help investigate diel activity and determine abiotic triggers of diel activity. Testing was undertaken to determine the following: 1) Can the TSPT capture dung beetles at eight (3-hr interval) time points throughout a 24-hr period? 2) How efficiently can the TSPT capture dung beetles compared to a ground-based pan trap? 3) How does the height of the TSPT (standing vs. buried) affect the species diversity and abundance? We found that the TSPT successfully captured dung beetles at different time intervals, providing an assessment of beetle activity. We provide examples from two locally abundant dung beetles species, Labarrus lividus (Olivier, 1789) (Aphodiinae) and Onthophagus binodis (Thunberg, 1818) (Scarabaeinae). The height of the TSPT negatively influenced species diversity and abundance compared to ground-based pan traps. When we compared the results of pan traps and the equivalent of a buried TSPT (TSPT lid with pan trap underneath set at ground height), no difference was detected in overall species diversity, yet abundance was still reduced. When the height of the TSPT was reduced, only 20% of the abundance was captured compared to the ground pan trap. Overall, the TSPT worked for the intended purpose of measuring diel activity though it should be buried or have its height reduced to improve capture rate.