Meeting Abstract
Understanding the factors responsible for heterogeneity in species diversity among different habitats is major challenge in evolutionary biology. The Amazon Basin harbors the highest species richness for a variety of groups, yet whether the Amazon is a cradle or museum of diversity continuous to be an open debate. In this study, we evaluate the phylogenetic relationships of an assemblage of beetles found in seven different habitats within a lowland tropical rainforest in the Ecuadorian Amazon. A set of 2 nuclear and 2 mitochondrial genes were used to infer a time-calibrated phylogeny of 31 species of Lachnophorini beetles (Carabidae: Coleoptera) from the western Amazon Basin. We determined the patterns of diversification using a lineage through time (LTT) plot to determine whether these beetles represent an adaptive or evolutionary radiation. The LTT analysis suggested a late-burst pattern of diversification. We complemented the phylogenetic relationships with a comprehensive dataset on the habitat occupancy of the species compiled during 4 years of fieldwork and 2-D geometric morphometric data. We used these datasets to ascertain whether the diversification pattern of the beetle species was associated with variation in habitat use and morphological differentiation. We found that Lachnophorini beetles late burst diversification was linked with significant disparity in morphological shape among the species assemblage. In addition, most of the morphological variation was structured according to microhabitat use. Together, the results obtained enables making inferences about the evolutionary mechanism that generated the large diversity of these beetles in the Amazon Basin.
