• Family: Halictidae
• Approximate # species in region: 99
• Common name: metallic sweat bees

It’s no wonder that Lasioglossum are often perceived as an identification quagmire by even seasoned bee taxonomists: there are many species of these small metallic bees, most are not as distinctly patterned to the naked eye as other species in the region, and their habitat associations are, for the most part, poorly known. Many of the species in this group are thought to exhibit some form of sociality, with species nesting both below ground and in decaying wood above ground.

Perhaps unsurprisingly, there aren’t too many obvious macroscopic characters that unite Lasioglossum as genus. Members of the diverse subgenus Dialictus are recognizable by their tiny size, metallic color, and black eyes (note that several other small bee genera, like Ceratina, Calliopsis, and Protandrena have greyish or colored eyes). Larger dark Lasioglossum might be confused with Halictus, but usually have their abdominal hair bands positioned at the base of each segment, rather than on the rim (make sure to also review the field marks of individual Halictus species!). The few Lasioglossum that do have hair bands on the rims of the tergites tend to have thinner, less distinct bands than Halictus. As far as species ID is concerned, we are currently limited to identifying just a handful of distinctive taxa in the field. While it seems certain that some Lasioglossum will never be separable from their closest relatives without specimens, we suspect that there’s still a long way to go to figure out which species and species groups are recognizable in the field – rigorous pairing of photographs and identified voucher specimens will be invaluable for improving our field ID resolution, and will hopefully help to dispel some of the fear around Lasioglossum identification!

Regional Species List: