Fine striped sweat bee

IUCN Red List

not listed

NatureServe

NNR - Unranked
SNR - Unranked

Minnesota

not listed

Fine striped sweat bee is a small, common, and widespread bee. In the United States it occurs in the east from Maine and Maryland, west to North Dakota and South Dakota, and south along the Appalachian Mountains, In the west it occurs from Washington and California, east to Montana and New Mexico. It occurs across southern Canada from Quebec to British Columbia. It is common in Minnesota.

The fine striped sweat bee was only recently recognized as a distinct species having been long grouped with the nearly identical Texas striped sweat bee (Agapostemon texanus). Distinguishing it from either Agapostemon angelicus or Agapostemon texanus has been a challenge even for specialists. Recent research has finally identified the specific physical traits that separate them. However, some of these features are not visible to the naked eye; they require high magnification, specialized lighting, and a very patient eye to be seen.

Females are 7⁄16″ (11 mm) in length. The entire head, thorax, and abdomen are brilliant green or bluish green. The hairs on the head and thorax are pale yellowish brown above, becoming whitish below.

The plate on the face above the upper lip (clypeus) is weakly convex and mostly green, black just on the lower third. The lower margin on the clypeus curves smoothly down to the hair fringe on the upper lip, it does not drop off sharply or slightly overhang the fringe. On the cheeks (genae) there is a series of fingerprint-like ridges (genal striations) behind the eyes. The ridges are extremely coarse and deep, and they generally curve away from the center of the throat and sweep toward the raised rim (the carina) that borders the underside of the head. The tongue is short. The compound eyes are light gray. The antennae have 13 segments: the long scape at the base, a short, more or less round segment (pedicel), and a whip-like third section (flagellum) with 11 segments (flagellomeres). Below the base of each antenna there is a single groove (antennal suture).

The largest plate on the upper side of the thorax is the scutum and the plate behind that is the scutellum. Both are shiny and doubly punctate, meaning that they have pits (punctures) of two different sizes: scattered, relatively sparse, deep punctures, intermixed with many more minute, closely spaced punctures. The last part of the thorax (propodeum), anatomically the first segment of the abdomen fused to the thorax, is encircled by a raised ridge. The cap-like plate over each wing base (tegula) is yellowish.

The legs are mostly brownish black except for the first segment (coxa), which is more or less greenish. On the front and middle legs, the third segment (femur) has yellow spots at the tip.

The wings are clear with yellowish veins. The basal vein is strongly curved.

The hairs on the abdomen are almost entirely whitish except for the hairs on the last segment, which are pale yellowish brown. On segments 2 through 4, the upper surface (tergite) has a whitish, powdery (pruinose) band on the front margin. The punctures on all tergites are separated with shiny areas between them.

Males are ⅜″ (9 to 10 mm) in length. The antennae have 12 segments, including 10 flagellomeres. The first flagellomere is two-thirds to three-quarters the length of the second. The scutum is not doubly punctate. The propodeum is not encircled by a raised ridge. On the hind legs, the femur is thicker than that of a typical bee but only moderately enlarged compared to some other members of the genus; it also has a small tooth on the underside. The femur and the fourth segment (tibia) of each leg are mostly yellow with dark areas and spots. On the hind legs, there is a dark spot on the underside of the tibia. The spot can range from taking up the lower half of the tibia to being completely absent. The abdomen is striped yellow and black. On the underside of the abdomen, the plate on the fourth segment (S4) has a swelling that reaches the rear edge of the plate on each side.

Size

Female total length: 7⁄16″ (11 mm)

Male total length: ⅜″ (9 to 10 mm)

Similar Species

Angeles striped sweat bee (Agapostemon angelicus)

Texas striped sweat bee (Agapostemon texanus)

Season

April to November

Behavior

Life Cycle

Larva Food/Hosts

Adult Food