Genetic and morphometric variation in Schwarziana quadripunctata and Schwarziana mourei (Hymenoptera: Apidae: Meliponini)

Abstract

Schwarziana bees are a ground-nesting stingless bee distributed in the Neotropical region. Schwarziana quadripunctata was the first described and the most studied species of this genus. Now, there are four valid species of Schwarziana bees, but it has been suggested that the diversity of this taxon may be higher, due to undescribed cryptic species. In this study, we investigated the populational diversity of S. quadripunctata using workers collected at 11 localities in Brazil (from the Northeast to South region). We also included one population of S. mourei (collected in São Paulo state, 2 nests). We analysed the bees using geometric morphometrics and molecular analyses amplifying mtDNA cytochrome oxidase I (COI) and 16S to access the diversity among the populations. From the results of geometric morphometrics, the Mahalanobis distances between S. mourei and S. quadripunctata are greater than those distances among S. quadripunctata populations. A similar scenario can also be observed looking to the phylogenetic tree generated by the molecular markers. Morphometry and molecular markers data showed significant association with geographic distance, indicating the existence of intrapopulation variation in S. quadripunctata. Our hypothesis was supported, that the populations of S. quadripunctata showed differences in haplotypic diversity. Overall, these analyses revealed a moderate level of intraspecific variation among S. quadripunctata populations and discriminated well the species S. quadripunctata from S. mourei.