1st Place: Diversity patterns of leaf litter weevils (Coleoptera: Curculionidae) along an elevational gradient in El Cielo Biosphere Reserve of northeastern Mexico

We studied communities of leaf litter weevils along an altitudinal gradient of 2000 m in northern Mexico, inside the Mexican Transition Zone, a region where nearctic and neotropical biotas interact. Overall richness (alpha-diversity) was 81 morphospecies, with 56 corresponding to leaf litter, and many undescribed species. Community structure (beta-diversity) showed more dissimilarity explained by species turnover rather than by nestedness. The interaction between tree size (measured as median DBH) and precipitation seasonality explained over 20% of weevil species richness variation: as precipitation increases along the gradient, weevils preferred bigger trees. Biogeographic affinity was estimated using all the currently available taxonomic and distribution knowledge of the studied taxa. Tropical leaf litter weevils increased in diversity with elevation, and were dominant across the altitudinal gradient, even in higher elevations. Despite a high inventory completeness (92%), not enough Nearctic taxa were found at the site to observe a clear pattern. Leaf litter weevil richness peaked at 1,600 m, whereas other Mesoamerican leaf litter invertebrates, like ants and dung beetles, peak at altitudes lower than 1,000 m.