SHARP-EATMAN
NATURE
PHOTOGRAPHY
GREEN SWEAT BEES
Tribe Augochlorini
Genera - Augochloropsis, Augochlora & Augochlorella
The sweat bee family, Halictidae, is a highly important group of wild pollinators. Sweat bees are instrumental in the cultivation of many commercial crops -- among them squash, legumes, sunflowers, watermelons, strawberries, tomatoes and peppers, to name but a few. Sweat bees are also essential pollinators of both garden flowers and native flora, and they are common visitors to wildflowers in the Lower Rio Grande Valley.
Sweat bees span 14 genera within the United States and a seemingly endless plenitude of species. Some sweat bees are black or dark with striped abdomens. Others -- members of the tribe Augochlorini and the genus Agapostemon -- are usually an eye-catching iridescent green.
Tribe Augochlorini:
Augochlora, Augochloropsis and Augochlorella sweat bees belong to the tribe Augochlorini. Bees in this tribe are brilliantly colored -- they usually range from golden-green to an intense pure green to a dazzling blue-green. Augochlorella and Augochlora sweat bees may be copper-colored or even metallic-pink as well.
Augochlorini tend to build nests in soil or, less commonly, in rotted wood. Some form large aggregations in the ground, constructing nests in clumps linked together by earthen connections.
Augochlorini sometimes act cooperatively, constructing nests that share a common entrance protected by a guard bee. Some Augochlorini are capable of shifting between solitary and cooperative behavior, depending on environmental conditions.
Some Augochlorella and Augochlora are considered to be “primitively eusocial”. They have a yearly life cycle split into spring and summer phases. In the first spring “foundress phase,” the bees construct an underground nest and provision it for offspring. When the young emerge, the males leave the nest, while the females remain in the nest, provisioning it for a second brood. When this second brood hatches in late summer, the males and females mate. The males die, and the inseminated females dig downward into the earth in the lower areas of their nests to overwinter. They emerge in spring to complete the colony’s life cycle.
Members of the tribe Augochlorini tend to be pollinator generalists. At the National Butterfly Center and in the Lower Rio Grande Valley generally, Augochlora, Augochloropsis and Augochlorella sweat bees visit the flowers of a varied range of plant families.
Distinguishing among green sweat bee genera
Augochlora, Augochloropsis and Augochlorella sweat bees sometimes can be difficult to distinguish from one another without the aid of magnification. Augochloropsis of the Valley tend to run larger than bees of the other two genera. Augochlorella tend to be smaller -- but some species are as large as typical Augochlora. Augochloropsis in the Valley also tend to be consistently green or blue-green, while Augochlora and Augochlorella appear in a myriad of colors, including various shades of green, coppery, or even a bright copper- pink.
Useful tips for distinguishing among green sweat bees genera include the following. (1) Upper legs: The upper legs of Augochloropis are bright iridescent green. This trait is visible to the naked eye and useful in the field. (2) Tegulae: The tegulae (the plates where the wings join the body) of Augochloropsis are metallic-green and D-shaped. The tegulae of Augochlora are oval and brown. The tegulae of Augochlorella are a pale reddish color and lack a distinct oval or D shape. (3) Forewings: If you have a macro lens, you also can distinguish green sweat bee genera by examining the marginal cells in their forewings. These differences are shown in the accompanying photo strip.
TAXONOMY OF GREEN SWEAT BEES
Order: Hymenoptera
Family: Halictidae (Sweat Bees)
Subfamily: Halictinae
Tribe: Augochlorini
Genus: Augochlora, Augochloropsis, Augochlorella
NBC Species:
Augochlora azteca (Aztec sweat bee)
Augochlora aurifera (Golden Augochlora)
Augochloropsis metallica (Green metallic bee)
Augochlorella bracteata (Gilded Augochlorella)
A female Aztec sweat bee (Augochlora azteca)
A female green metallic bee (Augochloropsis metallica)
A female Augochlorella
AUGOCHLORA vs. AUGOCHLOROPSIS vs.
AUGOCHLORELLA
Traits that help distinguish green sweat bee genera
This photo strip shows the differences among Augochlora, Augochlorella and Augochloropsis sweat bees.
AUGOCHLOROPSIS: This is a female Augochloropsis. In the Valley, bees of this genus are bright green or blue-green. The upper segments of Augocochloropsis legs are metallic green. (On females, the lower leg segments are darkly-colored.)
AUGOCHLOROPSIS: This is a male Augochloropsis. The bee's upper legs are metallic green like the female's (The lower segments of the male bee's legs may be light in color, as shown here.)
AUGOCHLOROPSIS: On an Augochloropsis, the tegulae (the plates where the wing attaches to the bee's body) are iridescent green and D-shaped.
ID GUIDE TO WILD BEES
OF THE NATIONAL BUTTERFLY CENTER
Mission, Texas
GREEN SWEAT BEES
Augochlora, Augochloropsis & Augochlorella
Aztec Sweat Bee
Augochlora azteca
Family: Halictidae
Size: 9 mm (female)
Associated flora
Alamo vine
(Merremia dissecta)
Plant Family: Convolvulaceae
Esperanza
(Tecoma stans)
Plant Family: Bignoniaceae
Prickly Pear
(Opuntia engelmannii)
Plant Family: Cactaceae
When seen:
September & November 2018
April 2019
A female Aztec sweat bee inside a yellow prickly pear blossom: within the United States, this species is found only in south Texas. It also inhabits Mexico.
Aztec sweat bees tend to have a brilliant blue-green iridescence.
Dorsal view of bee
A brilliant blue-green female Aztec sweat bee (Augochlora azteca)
A brilliant blue-green female Aztec sweat bee (female)
Golden Augochlora
Augochlora (Oxystoglossella) aurifera
Family: Halictidae
Size: 6 mm (male)
6-7 mm (female)
Asssociated flora:
Cowpen Daisy
(Verbesina encelioides)
Seaside goldenrod
(Solidago sempervirens)
Plant Family: Asteraceae
Spiked Malvastrum
(Malvastrum americanum
var. Americanum)
Plant family: Malvaceae
When seen at the NBC:
April - November
This is a female Augochlora aurifera. It is smaller than the Augochlora azteca shown above. This bee has golden-green iridescence.
The female Augochlora aurifera has reddish-brown jaws and legs, and bright reddish coloration on the joints between the bee's tibiae and femurs.
A male Augochlora aurifera
Frontal view of a male Auguchlora aurifera from above
A female Augochlora aurifera
A male Augochlora aurifera
Green Metallic Bee
Augochloropsis metallica
Family: Halictidae
Size: 9 mm (male); 9 mm (female)
Asssociated flora:
Silver-leaf Nighshade
(Solanum elaeagnifolium)
Plant family: Solanaceae
Hierba del marrano
(Symphyotrichum subulatum)
Plant Family: Asteraceae
Erect Spiderling
(Boerhavia erecta)
Plant Family: Nyctaginaceae
When seen at the NBC:
April - November
This is a female Augochloropsis metallica. Bees of this species often have an intense blue-green iridescence.
A female Augochloropsis metallica: note that the tegula (the plate where the wing joins the body) is predominantly iridescent green.
The top leg segments of the female Augochloropsis are iridescent green. The lower segments are dark and covered with white hairs, and the feet (tarsi) are reddish brown.
A male Augochloropsis metallica: note that the bottom segments of the male bee's legs are white, with sparse white hairs. The top segments are metallic green.
Close-up of the hind leg of a male Augochloropsis metallica
Dorsal view of male bee: note the D-shaped iridescent green tegulae (the plates where the wings meet the body). This is a distinguishing trait of both male and female bees of the genus Augochloropsis.
A female green metallic bee (Augochloropsis metallica)
Close-up of a female green metallic bee (Augochloropsis metallica)
A male green metallic bee (Augochloropsis metallica)
Green Sweat Bee Species of the National Butterfly Center
Gilded Augochlorella
Augochlorella bracteata
Family: Apidae
Size: 5-7 mm (female)
4.5-6 mm (male)
Asssociated flora:
Scorpion-tail
(Heliotropium angiospermum)
Family: Boraginaceae
When seen: April - November
A male Augochlorella bracteata
This male Augochlorella bracteata has a coppery-pink color iridesence. Bees of this species are often green or yellow-green.
Lateral view of a male Augochlorella bracteata
Face of a male Auguchlorella bracteata: the bee's face is slightly wider than it is long, and it is covered with fine white hairs. Part of the labrum is yellow. The clypeus is metallic, with the exception of two pale markings near the apical rim. The jaws are reddish.
A male Augochlorella bracteata
CITE THIS PAGE: Sharp, Paula and Ross Eatman. "Augochlora, Augochlorella and Augochloropsis." Wild Bees of the National Butterfly Center of Mission, Texas. 15 Jan. 2019, http://www.wildbeestexas.com. Accessed [day/month/year guide accessed].