Minnesota Ants, Bees, Wasps and Sawflies

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.

There are more than 2,000 living species of sweat bee (Family Halictidae) worldwide. They are so named because they are attracted to the sweat of humans. Fortunately, they seldom sting and when they do the sting is minor.

There are four species of Augochlora in the United States, only one of which is found in Minnesota. Pure green augochlora (Augochlora pura) is a moderately-sized, solitary, metallic green sweat bee. It is very common in the eastern half of North America west to Minnesota. It is found from April to October in woodlands and nearby thickets and pastures.

The overwintered mated female emerges in April. Using an existing insect burrow in dead wood as a starting point, she digs a nest consisting of many branched burrows. She places a pollen ball and nectar in each burrow then lays a single egg on the pollen ball. The first generation offspring emerge as adults in June. By the end of June they have constructed their own nests. The larvae or pupa of the last generation overwinter and emerge as adults the following spring. Adult females overwinter beneath rotting logs in a state of diapause. Males die in the fall.

Sweat bees are identified by a short tongue with a short, pointed last segment; single groove below the base of each antenna; lobe at the base of the hindwing longer than the submarginal cell; and basal vein on the wing strongly arched. Pure green augochlora is distinguished by the completely bright metallic green or coppery body; abdomen not conspicuously striped; dark brown, oval-shaped structure at the base of each wing; wing with three submarginal cells, the first longer than the third; marginal cell of the wing squared off at the end; and upper margin of the plate on the upper lip intruded upon by lobes of the plate above it.

elm sawfly (Cimbex americana)

metallic bluish-green cuckoo wasp (Chrysis angolensis)

eight-toothed cuckoo leaf-cutter bee (Coelioxys octodentata)

alfalfa leafcutting bee (Megachile rotundata)

sand-loving wasp (Tachytes distinctus)

half-black bumble bee (Bombus vagans)