Different ways of constructing octaves and their consequences on the prevalence of the bimodal species abundance distribution

Several studies on dung beetle communities suggest that their species abundance distribution is bimodal. This bimodality has been explained as a consequence of the mixture of local and non-local species in the communities. In this paper we demonstrate that bimodal distribution in dung beetles is a consequence of the method of octave construction, which increases the number of species present in the first octave. Although we do not rule out the existence of bimodality in species abundance distributions, we suggest that this should be confirmed by large sampling programs done at local and regional levels, and by the correct application of the octave construction method.