Barcoding as a useful tool for South American wild bee systematics

GONZÁLEZ VAQUERO, R.; ROIG ALSINA, A.

Guelph

Congreso; 6th International Barcode of Life Conference; 2015

University of Guelph

The bee genera Corynura and Halictillus (Hymenoptera: Halictidae) contain species that are very abundant in Chile and Argentinean Patagonia, and which are key elements in southern South American ecosystems. For instance, C. chloris is among the major pollinators of crops such as raspberry, Chilean hazel, and buckwheat as well as native wildflowers. These bee species are very difficult to identify due to close morphological similarity among species and extreme sexual dimorphism. To assess this, we analyzed the barcodes of 15 species of Corynura, as part of a revision of the genus, as well as four species of Halictillus. Results: We obtained 170 barcode-compliant sequences. Barcodes were useful to confirm gender associations and to detect two cryptic species previously considered as one. The genera showed a median interspecific distance (13.5%?14.3%), considerably higher than among other closely related halictid genera. The sequence divergence between specimens of the same species was up to 0.9%, with a few exceptions. The barcodes of five specimens differed from the rest by more than 2%, although these individuals were not morphologically different from the others, nor collected in distant areas. In contrast, C. patagonica showed a distance of 4.2% when any of the specimens from Chile was compared to those from Argentina. The only morphological difference found between the barcode clusters was the colour of the metasomal terga of the female. BIN analysis was useful to identify the species that showed high intraspecific variation. Significance: Species delimitation and identification is particularly important in halictine bees, which are renowned for being morphologically monotonous. The results suggest that Corynura and Halictillus species can be identified through DNA barcodes, although some species showed a high intraspecific variation which requires further study. We conclude that C. patagonica is probably two cryptic species.