Comparative Analysis of the Ecological Functions of Dung Removal and Seed Dispersal among Two Telecoprid and Two Paracoprid Dung Beetles (Coleoptera: Scarabaeidae: Scarabaeinae)

Abstract

We evaluated the functional capacities of dung removal and secondary seed dispersal by two telecoprid dung beetles, Canthon rutilans cyanescens (Harold) and Deltochilum multicolor Balthasar, and two paracoprid dung beetles, Dichotomius sericeus (Harold) and Phanaeus splendidulus (Fabricius), in a remnant of Atlantic Forest in southern Brazil. We aimed to describe and understand the variability of these behaviors among these species and compare their dung removal capacities by standardized biomass. Two experiments were conducted to evaluate the effect of exposure time to the resource on the functional capacity of the four species and the effect of density on C. r. cyanescens and D. sericeus in arenas with single male/female pairs or groups of three pairs. Beetles were exposed to 30 g of canine feces with artificial seeds, which remained in the field for two, seven, or 21 days in four replicates. The paracoprids were more efficient than the telecoprids in all ecological functions. Canthon r. cyanescens removed significantly more dung with increasing exposure time and density, while D. multicolor showed no significant differences in any ecosystem function. For D. sericeus, time was relevant for increasing dung removal and dispersion of large seeds, while density only affected dung removal. Phanaeus splendidulus removed more dung with increasing exposure time, but its effect on seed dispersal was not significant. When evaluating dung removal capacity by standardized biomass, C. rutilans and D. sericeus were the most efficient species, demonstrating that paracoprids are usually more efficient because of their greater body biomass. As much as the functional capacity of certain ecological functions differs among species, different functional groups provide complementarity in communities. Thus, data on the biology and behavior of species are important in ecosystem functions.