What is driving the community structure of insects in arid ecosystems of Southern Africa? An example with blister beetles (Coleoptera: Meloidae)

Abstract

A considerable part of community ecology literature questioned what are the main drivers of ecological relationships in an organismal community. We analysed this focal question by studying blister beetle (Meloidae) assemblages in Southern Africa. We explored the ecological distribution of 48 species across underlying bioclimatic (e.g. temperatures and precipitation regimes), environmental factors (biomes, vegetation structure) and the taxonomic heterogeneity of each groups inhabiting major biomes of Namibia across their main biological and ecological traits, by Canonical Correspondence in order to get an ordination plot. Monte Carlo methods were used to test for randomness of the data ordination. Ordination plot identified three main assemblages, one being constituted by strictly semiarid savannah species (camelthorn, mountain, karstweld, thornbush, mixed tree and shrub, dwarf shrub, mopane and forest savannahs), one much larger and less homogenous second assemblage, inclusive of more generalist species from Karoo and semi-desert habitats, living also in arid savannahs, and the third one including Nama Karoo species. All the three assemblages were taxonomically very heterogeneous, showing that phylogenetic relationships are probably less relevant than interspecific ecological relationships among species of the same group to determine present-day community structure in these animals.