Nomad Bees are an abundant and confusing taxon. As a group, they are distinctive klepoparasites, primarily of Mining Bees (Genus Andrena). The vast majority of species are active in the spring and very hard to identify, especially from photos. A few species emerge in late summer and fall and are more likely to be identified from photos.
Genus level ID – To the untrained eye, Nomad Bees are probably appear more like a wasp than the stereotypical bee. Most Nomad Bees are colorful and appear mostly hairless, though some have noticeable hairs on some body parts. The background color of the body is usually red or black and most have yellow marks of sorts. Females tend to be larger and redder, while males are often hairier and blacker, though there is significant inter and intra species variation.
Similar genera – Blood Bees (Sphecodes) are another cleptoparasitic genera that often co-occurs in good nesting habitat. In Vermont, any red on Blood Bees is limited to the abdomen and none have any yellow.
“Distinctive” Spring Nomad Bees
Fall Nomad Bees
Unless otherwise specified, photos are courtesy of Margarita Miklasevskaja at PCYU with funding from NSERC-CANPOLIN.