Can Baited Pitfall Traps for Sampling Dung Beetles Replace Conventional Traps for Sampling Ants?

Ants and dung beetles are widely used in monitoring biodiversity and are considered excellent environmental indicators. Although the pitfall trap is the most commonly used method to sample dung beetles and ants in ecological studies, beetles are usually sampled using dung-baited pitfall traps while ants are sampled using un-baited pitfalls. In the protocol for collecting the beetles it is necessary to have attractive baits in pitfalls. In order to minimize collection effort and costs and to facilitate logistics, it is necessary to determine if there is an effect of the baits on the biodiversity of ants collected in the same traps. Therefore, the objective of this work was to find out whether baited pitfalls could replace conventional pitfalls for the capture of ants. In a total of 42 areas of native habitat, three baited pitfall traps and three without bait were installed, all in the same transect, equidistant ten meters and in activity for 48 hours. In total, 150 species were collected, of which 131 were recorded in non-baited pitfalls and 107 in baited pitfalls. Traps without bait contributed to 28% of the total number of species captured in this study, whereas pitfalls with bait contributed only to 12% of the total species caught. However, 60% of the total species were captured regardless of the method. In addition to the loss of species among the types of traps, the effect of the method modifies the species composition. We concluded that depending on the type of study, a small decrease in the number of species and change in the composition can influence the results. Thus, we recommend that baited pitfalls should not replace conventional pitfalls.