blood bees

Sphecodes is a very large genus of small bees known as blood bees. There are 319 valid described Sphecodes species worldwide as of 2015, 72 species in North America north of Mexico, and at least 23 species in Minnesota.

Blood bees are found on every continent except Antarctica. They occur in every state in the United States and in every province in Canada except for the Northwest Territories.

Like other cuckoo bees, blood bees do not construct nests. They are kleptoparasitic, meaning they lay their eggs in the nests of other ground-nesting bees in the family Halictidae, especially in the genera Lasioglossum, Halictus, Augochlora, Augochlorella, and Augochloropsis.

The female enters a host nest, kills the host’s eggs, and lays one of her own. In some species the female resides in the nest of the host, living alongside the host, and possibly taking over the role of queen.

Adult blood bees feed on flower nectar. They do not collect pollen because the young feed on the pollen collected by the host species.

Blood bees resemble wasps in appearance and behavior. They have no pollen-collecting hairs (scopa), and their bodies are relatively hairless. Like wasps, they hover low over the ground searching for hosts nests.

Blood bees are 5⁄32″ to ⅝″ (4 to 15 mm) in length. The body is strongly and deeply pitted (punctate). Almost all have a bright blood red abdomen. This is the feature that gives the genus its common name. On some the abdomen is only partly red. Rarely the abdomen is entirely black. All have a black head and a shiny black thorax. The tongue is short and pointed. The antennae have 12 segments on the female, 13 segments on the male. There is just a single line-like groove extending downward from the base of each antenna (subantennal suture).

There are branched hairs on the pronotal lobe, but this cannot be seen without a microscope.

The legs are slender, even spindly, and have no pollen collecting hairs.

On the forewing, the basal vein is strongly curved, like a sideways J. On the hind wing, the lobe at the base (jugal lobe) is longer than the submedian cell.

Sources

4, 24, 27, 29, 30, 72, 82, 83.

Common

Sphecodes sp. Blood bee

Sphecodes sp., blood bee, on goldenrod flowers, Barnes Prairie, Racine Co., WI. Photographed October 6, 2022.

Location: Saint Paul, MN

Found while clearing last fall's leaves out of a flower bed

Location: Barnes Prairie, Racine Co., WI

Sphecodes sp., blood bee, on goldenrod flowers, Barnes Prairie, Racine Co., WI. Photographed October 6, 2022.

Location: Woodbury, MN