Multifactorial structuring in a local guild of coprophilic scarab beetles from the Mexican transition zone: Analyses of ecological hypotheses

Different hypotheses have been proposed to explain the environmental gradients‐biotic structuring relationship. Nevertheless, several inconsistencies have arisen when only one hypothesis is chosen to explain the biological diversity patterns. Our aim is to test a multiple hypotheses approach to explain the structure of a coprophilic scarab local guild.

Coprophilic Scarabaeoidea beetles were sampled for 33 sites along the study region (Los Chimalapas, Oaxaca, Mexico). Several environmental variables were used to test four hypotheses for geographic gradients: Productivity, ambient energy, habitat heterogeneity and temporal heterogeneity. Generalised linear mixed models were used to test the relationship of the hypotheses on the abundance, species richness and Shannon‐Wiener diversity of the local guild. Moreover, canonical correspondence analysis was performed to analyse the effects on species composition.

Abundance was negatively affected by the simultaneous effect between two habitat heterogeneity factors, while both species richness (positive effect) and Shannon‐Wiener diversity (negative effect) were mainly related to productivity, and species composition was mainly explained by habitat heterogeneity.

We conclude that multiple hypotheses, both based on species‐energy and heterogeneity, need to be considered to explain biotic setting of communities, ensembles, assemblages, local guilds and other complex biotic systems.