Beginner's guide to Vermont Green Bees.
The purpose of the colored boxes (in the chart below) is to highlight the shared taxa of these green bees at the Family and subfamily, thus being an easier-to-ID taxa level for the VT green bees. Then, if you are confident enough to go further, and can distinguish between the Halictini and Augochlorini but not the genus, make your ID at that level. If you can get to Agapostemon, choose Subgenus agapostemon as all Agapostemon in VT are subgenus Agapostemon.
Tribe | Genus | Subgenus | A. BINOMIAL NAME (Genus _ species (epithet)). | Common Name |
Halictini | Agapostemon | Agapostemon | Agapostemon sericeus | Silky Striped Sweat Bee |
Halictini | Agapostemon | Agapostemon | Agapostemon splendens | Brown-winged Striped Sweat Bee |
Halictini | Agapostemon | Agapostemon | Agapostemon virescens | Bicolored Striped Sweat Bee |
Halictini | Agapostemon | Agapostemon | Agapostemon subtilior* | Fine Striped Sweat Bee |
Augochlorini | Augochlora | Augochlora | Augochlora pura | Pure Green Sweat Bee |
Augochlorini | Augochlorella | None | Augochlorella aurata | Golden Sweat Bee |
Augochlorini | Augochloropsis | Paraugochloropsis | (Augochloropsis viridula) | Northeastern Sweat Bee** |
*Formerly known as Agapostemon texanus
**Formerly Augochloropsis metallica (Metallic Epaulated-Sweat Bee)
Agapostemon: All females have a green abdomen except for Agapostemon virescens, which has a black abdomen with white stripes. Females have a raised rim around the propodeum, and both males and females have gray-green compound eyes.
Agapostemon males have a black abdomen with yellow stripes, yellow legs, and a yellow labrum (upper lip).
Males of all 4 Agapostemon species are usually not identifiable from photos.
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Silky Striped Sweat Bee (Agapostemon sericeus) Females can show some white hair in stripes on the abdomen, but the background color is bright green, not black as in the Bicolored (A. Virescens).
Look for a metallic green head and thorax. The key differences are based on sex: males have a distinctive yellow and black striped abdomen, while females are metallic green with silvery-white abdominal bands and a rough thorax.
The male abdomen has a flat, yellow and black striped pattern that may look duller compared to the bicolored species' vibrant metallic sheen. Yellow spots on the sixth abdominal segment.
Similar species: Females are challenging to separate from Brown-winged Striped Sweat Bee (Agapostemon splendens) and Fine Striped Sweat Bee (Agapostemon subtilior).
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Brown-winged Striped Sweat Bee (Agapostemon splendens) A. splendens is not expected in VT except at best as a rarity in dune habitat. Females are likely recognizable by their dark brown wings, while males may be recognized by their massively swollen hind femur.
A rare metallic green sweat bee with dark brown wings (females) or massively swollen hind femurs (males).
Similar species: Similar to the more widespread Silky Striped Sweat Bee (Agapostemon sericeus) and Fine Striped Sweat Bee (Agapostemon subtilior).
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Bicolored Striped Sweat Bee (Agapostemon virescens): The combination of the green thorax and the black-and-white striped abdomen is unique in our area. Males, which are only active at the end of the season, have a yellow and black striped abdomen like the other males in the genus. Unlike other species, male Bicolored tend to be dark under the abdomen. Medium-sized bee with a metallic green head and thorax. Females have a black and white striped abdomen.
Males are difficult to ID to species without a view of sternites. Consider revising species-level IDs to Subgenus Agapostemon if the diagnostic characters of species cannot be verified.
Similar species: Female Silky Striped Sweat Bee (Agapostemon sericeus) can occasionally have faint white hair bands on the abdomen, but on a green background.
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Fine Striped Sweat Bee (Agapostemon subtilior*) Metallic green sweat bee and then check for a thickened or "toothed" black mark on the male clypeus (faceplate), yellowish hairs on the thorax and legs, and a distinct dark mark on the basal (lower) part of the hind tibia for both males and females. Females are entirely metallic green, while males have metallic green heads and thoraxes with black and yellow striped abdomens. Look for a smooth, shiny scutum on the females.
*Formally known as Agapostemon texanus
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Tribe Augochlorini
Characteristics include black mandibles with two similarly sized teeth, dark brown wings, a well-developed paraocular lobe, sharp inner margins on the compound eyes, and a uniformly smooth scutum. Also, females have a central keel on the first sternite (S1).
Pure Green Sweat Bee (Augochlora pura): Augochlora has a metallic green head, thorax, and abdomen. The forked mandible is rarely visible in photos, but distinctive. Small to medium-sized, metallic green sweat bee (5–9 mm long) with shiny, bright green head, thorax, and abdomen.
Distinguishing features include a uniformly smooth scutum (A bee's scutum is the shield-shaped, large, and often hair-covered section of the thorax located between the head and the wings), dark brown wings, and the propodeal triangle (a plate above the back of the thorax) with striations that completely traverse it. Squared-off (truncated) marginal cell at the end of their wings. Note head shape and clypeal lobe, etc.
Similar species: Often impossible to confidently separate from Golden Sweat Bees (Augochlorella aurata) without clear photos.
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Golden Sweat Bee (Augochlorella aurata) Augochlorella has a smaller head than Augochlora, mandibles with one main tooth and a small subapical tooth, a square paraocular lobe, and a rounded inner margin on the compound eye (the eye is narrower at the top than at the bottom). The abdomen is curved and teardrop-shaped, and the wings are light brown.
The end of the mandible of females is shaped like a mitten, though this is often not visible in photos. While variable in size, this tends to be the smallest green bee in VT. Especially small and golden individuals are probably safely ID without seeing finer details.
Small, metallic green bee (5-7mm) that can have golden, yellow-green, or coppery-green colors, sometimes with coppery-pink hues. Key features include rounded mandibles (shaped like a mitten) that distinguish it from A. Pura with its forked tips, and an unridged propodeum (unlike Agapostemon)
Most similar to Pure Green Sweat Bees (Augochlora pura), many won’t be identifiable from photos. They are similarly sized and have the same metallic green coloration.
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Augochloropsis has one distinct feature that separates it from the other three genera — large, asymmetric or angular tegulae that are usually extensively green. On the first and second abdominal segments (T1 and T2), there is a row of stiff hairs, sparse on some species and dense on others.
Ranging in length from 6 to 12 mm (0.28 to 0.5 inches), Augochloropsis species are typically larger than bee species in the genera Augochlora and Augochlorella. Like the other green sweat bee genera, this genus has a metallic green head, thorax, and abdomen.
Females with pollen-collecting hairs on hind leg femora and tibiae. Forewing with three submarginal cells and curved basil vein. Males and females with green trochanter, femur, and tibia. (Upper leg).
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Northeastern Sweat Bee (Augochloropsis viridula**):
The green, bean-shaped tegula is distinctive, though not always obvious. Brilliant metallic green bee that is larger than other green sweat bees, with a broad, bell-shaped abdomen. Key distinguishing features include D-shaped, metallic green tegulae (wing bases) and bright metallic green upper legs.
Males and females have green trochanter, femur, and tibia. Forewing with three submarginal cells and a strongly basil veined. Large, asymmetric, or angular (not oval but bean-shaped) tegulae (where wings join body) that are usually extensively green. On the first and second abdominal segments (T1 and T2), there is a row of stiff hairs, sparse on some species and dense on others.
Similar species: Slightly smaller than Striped Sweat Bees (Genus Agapostemon) without the angular end of the thorax. Larger and brighter than the Pure Green Sweat Bee (Augochlora pura).
**Formerly Augochloropsis metallica (Metallic Epaulated-Sweat Bee)
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* Data from various sources, including: Vermont Center for EcoStudies, Bee Watching, Minnesota Native Bees, Wikipedia, and Zookeys*. Any errors should be attributed to me and not the source data.
- Comparison photos - Very helpful for ID to Genus and Species
- VCE Green Bee Genera of VT
- ID Keys *ZMPortman, M. Arduser, I.G. Lane, and D. P. Cariveau. Three at the dept. of Entomology, Univ. Minnesota, one Arduser, at the Conservation Research Institute, Cedarburg, WI.
- Bee Anatomy definitions
- KEY: WI Agapostemon Species (4) - texanus, virescens, sericeus, splendens (Author Denny Johnson)
For further Green bee ID guide view: North American Halictid Green Bee Genera Quick Guide Agapostemon, Augochloropsis, Augochlora, Augochlorella
Clare Maffei, USFWS Native Bee Inventory and Monitoring Lab, July 2021
