Minnesota Ants, Bees, Wasps and Sawflies

There are more than 850 species of nomad bee (Nomada sp.) worldwide, more than 280 species in North America. Like other cuckoo bees (subfamily Nomadinae), nomad bees do not construct nests, but lay their eggs in the nests of ground-nesting bees. One to four eggs are laid in the cell wall of the host nest. The larvae have large, outward-facing, scissor-like mandibles. The first larva to emerge destroys all the other eggs, both those of the host and those of its own siblings. It consumes the pollen provisioned by its host, and emerges as an adult the same time as the host adults emerge.

Nomad bees are usually black, black and red, or entirely red, with yellow, white, and/or red markings. Many species have red legs. The genus Nomada includes the only bees in North America that are entirely red. They have short, thin, and inconspicuous hairs on the body and no pollen-collecting hairs (scopa) on the hind legs. They look more like wasps than a bees.

Downy yellowjacket (Vespula flavopilosa) is an uncommon, medium-sized, predatory, social wasp. It is found in the northeastern United States from Minnesota to Maine, south to Virginia, and along the Appalachian mountains to northern Georgia. It closely resembles eastern yellowjacket. It is thought by some to be a hybrid between eastern and common yellowjackets. Others suggest that it probably arose as a hybrid but now queens mate with drones of the same species.

The overwintering queen emerges from hibernation in April or May. She builds a nest of 20 to 45 cells and cares for the grubs as they hatch. In about 30 days the workers emerge and take over nest building duties. Through spring and summer the queen produces a large number of worker wasps. In mid-summer, the nest grows exponentially, as more and more workers become available, ultimately with 3,500 to 15,000 cells. Only the new queens survive the winter, hibernating under loose tree bark, in a decaying stump, or in another sheltered location.

In eastern North America, four yellowjacket species, common, downy, eastern, and German yellowjackets, closely resemble each other, making identification difficult. Downy yellowjacket is distinguished from the others by a continuous, uninterrupted yellow band on the face below the compound eye; and by the shape and pattern of black markings on the first and second abdominal segments.

Two-spotted bumble bee (Bombus bimaculatus) is small, colonial bumble bee. It is common in eastern North America and in Minnesota. It emerges very early in the spring and is active until mid-summer.

Two-spotted bumble bee usually nests underground but sometimes in the cavity of a dead tree. Like other bumble bees, it will sting to protect itself or its nest. The stinger is not barbed and the bee can sting multiple times. It feeds on the pollen and nectar of flowers. It has a very long tongue that allows it to feed on nectar of plants with long corolla tubes.

Two-spotted bumble bee is identified by the thorax which is yellow except for a small, round, black spot in the middle; the first abdominal segment is entirely yellow, the second has a broad, yellow, W-shaped spot in the middle, and the remaining (on the female) are all black; and the hairs on the back of the head are yellow.

Brown-belted bumble bee (Bombus griseocollis) is a small, very common, colonial, ground-nesting bumble bee. It is the second most common bumble bee in eastern North America, after only the common eastern bumble bee. It is less common in Minnesota and the other northernmost states.

Bumble bees are the first bees out in the spring and the last bees out in the fall. Brown-belted bumble bees emerge earlier in the spring than most other bumble bees. They nest in the ground in small colonies of 50 or fewer individuals.

Brown-belted bumble bee is identified by the thorax which is yellow except for a small, round, black spot in the middle; the first abdominal segment is entirely yellow; the second has a single yellow, narrowly U-shaped spot in the middle and a brown band that swoops around the yellow spot; and the remaining are all black.

There are over 750 species of gall wasps (Family Cynipidae) in North America. They are all tiny and look pretty much alike. Fortunately, most can be identified by the appearance, location, and host species of the abnormal growths (galls) their larvae produce.

Oak flake gall wasp (Neuroterus floccosus) galls are found on the underside of leaves of bur oak and swamp white oak. They occur singly though there are usually several galls on any one leaf. They are hemispherical, thickly hairy, and ⅛″ to 3 ⁄16″ in diameter including the hairs. The hairs are white at first but soon turn brown. Each gall contains a single chamber and a single wasp larva. It is revealed on the upper leaf surface as a smooth blister-like bump.

grass-carrying wasp (Isodontia mexicana)

thread-waisted wasp (Sphecinae)

potter wasp (Eumeninae)

fraternal potter wasp (Eumenes fraternus)

pure green augochlora (Augochlora pura)

yellow-faced bee (Hylaeus sp.)

acorn plum gall wasp (Amphibolips quercusjuglans)