Andrena are commonly referred to as "mining bees," because they construct underground nests (a feature shared with many other native bees). Although solitary, Andrena commonly nest close by one another, sometimes forming collective populations numbering in the tens of thousands. In such “bee cities” (properly called aggregations), each female usually builds her own nest and individually supplies it with food.
Throughout North America, Andrena are essential pollinators of native wildflowers, orchard crops and garden plants. As a rule, Andrena are non-aggressive and their stingers too fragile to sting humans; if approached, they zoom quickly away.
The genus Andrena is sparsely represented in the Lower Rio Grande Valley. Nonetheless, Andrena is one of the largest bee genera in the world and the most diverse in North America, comprising 400 species on this continent and nearly 1500 worldwide. There are more than 100 Andrena species in the state of Texas alone.
Andrena flourish in temperate areas and seem immune to cold: they emerge just after winter ends even in northern Canada. In most of the United States, Andrena eschew the heat of summer and are most active in spring and fall.
In subtropical areas like the Lower Rio Grande Valley, many Andrena species emerge only in March and April and are rarely seen at other times of year. Within the western hemisphere, Andrena populations appear only in North America; they do not extend into the hotter areas of the subtropics.
In the last 100 years, fewer than a dozen Andrena species have been recorded in or near the Lower Rio Grande Valley. These include: Andrena accepta (Cameron Co.); Andrena andrenoides (Cameron Co.); Andrena faceta (Cameron & Hidalgo Cos.); Andrena flaminea (South Texas); Andrena micheneri (Cameron Co.); Andrena nothoscordi (Cameron Co.); Andrena plebeia (Starr Co.); Andrena primulfrons (Hidalgo Co., Val Verde Co., and Nuevo León) and Andrena trapezoidea (Cameron Co.).
With the exception of one undescribed species of the subgenus Andrena (Opandrena), the Andrena miserabilis shown here is the single Andrena species encountered by this website's authors in the Lower Rio Grande Valley between 2017-2023. E.T. Cresson first described Andrena miserabilis in his 1872 publication Hymenoptera texana, after examining male and female bees found in Texas.
Most Andrena are honey-bee-sized or smaller. Andrena often look "furry" -- they have hairy thoraxes, faces and legs. The bees' faces and bodies tend to be black. Their abdomens are dark and usually striped with bands of pale hair. In South Texas, some Andrena have red or partly-red abdomens.
All Andrena species share a distinctive facial characteristic: Andrena have two "sutures" (seams) under each antenna. Facial depressions called foveae rest alongside the sutures. As shown in the accompanying photographs, on female bees, the foveae are covered with hairs that are sometimes described as looking like "sideways eyebrows". The faces of male bees are covered with shaggy patches of hair.
A second distinguishing Andrena trait is that female bees' scopal hairs are located on their upper hind legs; they look as if carrying pollen under their "armpits". Because Andrena are generally hairy, pollen also tends to cling to their heads and thoraxes inadvertently as well; the bees often look as if they had been rolled in corn flour.
TAXONOMY OF ANDRENA BEES
Genus: Andrena (mining bees)
Species found at the NBC:
Andrena (Larandrena) miserabilis
A female Andrena mining bee
A female Andrena mining bee
A male Andrena mining bee
TRAITS OF THE GENUS ANDRENA
A female Andrena
Andrena typically have dark heads and bodies; their abdomens are often striped with pale hair bands. Some Andrena of the Valley have red abdomens.
A male Andrena: males are slenderer than females, and often covered with fine hairs.
The faces of Andrena have two sutures (seams) accompanied by depressions called facial foveae. On female Andrena, these foveae are covered with hairs, giving the bees the appearance of having "sideways eyebrows".
Female Andrena tend to have dark faces.
The faces of male Andrena often have ivory or pale-yellow clypei.
Andrena Species of the National Butterfly Center
Miserable mining bee
Andrena (Larandrena) miserabilis
Size: 8-9 mm (female)
7- 9 mm
The bees shown here nested in a prickly pear cactus grove surrounded by blooming honey mesquite trees (Prosopis glandulosa)
March & April 2019 and 2021
A female Andrena miserabilis. The bee's abdomen is blackish brown and smooth and encircled with bands of pale hairs. Note the rust-colored hairs rimming the rear of the female bee's thorax.
Dorsal view of female bee
The bee has a broad, squarish face, with dark mandibles and antennae. Long strips of pale hair cover the female’s facial foveae, extending from each antennal socket to just above the clypeus.
A male Andrena miserabilis. Males are slender and covered with fine, golden-brown hairs. The pale hair bands on their abdomens are weakly-defined.
The male Andrena miserabilis has a yellow clypeus with two black dots located near the tentorial pits. Males’ antennae are generally dark, but often reddish underneath the flagellum, and their mandibles sometimes have amber tips.
Close-up of an Andrena miserabilis forewing: the wing has 3 submarginal cells. According to Charles D. Michener, Andrena miserabilis can be distinguished from similar mining bees of the subgenus Parandrena by this trait. (The forewings of Parandrena have only two.)
A male Andrena miserabilis
A female Andrena miserabilis
Andrena miserabilis is known as the "miserable mining bee" for no readily explained reason – the mystery of this bee’s name remains buried in the catacombs of bee taxonomy. The bee seems no more miserable than other members of its genus – except perhaps for the fact that it emerges very early in the spring, when the weather is still chilly -- as early as March in the Lower Rio Grande Valley.
Miserable mining bees emerge in the Lower Rio Grande Valley just as willows and honey locust begin to bloom. The female bee shown here had built a nest in a large aggregation of miserable mining bee females, situated in an area covered entirely with prickly pear cactus. The Andrena ignored the cactus, but probably gathered pollen from blossoming trees in the general area.
This is a widespread mining bee species. Andrena miserabilis is found throughout the United States, from the East to the West Coast, as far north as Canada. It occurs as far south as Tamaulipas.
Identification Information: Andrena miserabilis is the sole North American member of its subgenus, Larandrena. Female miserable mining bees have dark faces and bodies, and abdomens banded with pale hairs. Their hind-leg scopal hairs are white and long. Female bees can be recognized by the traits highlighted in the accompanying photo strip: (1) They have broad facial foveae that extend fairly high up on their faces; (2) the bees' clypeuses are shiny and black; and (3) the back of the female bee's thorax is rimmed with a tuft of rust-orange hairs.
Male bees are dark and slender, with heads and bodies covered with fine golden-brown hairs. Males have pale yellow masks on the lower part of the face (known as the clypeus), dotted with two black markings that look like false nostrils. Some males also sport long, curved jaws that meet in the middle, like scissors made of scimitars. Males use their jaws to fight one another. The forewings of both male and female miserable mining bees are glassy-brown with brown veins, and their tegulae are brown to dark brown.
CITE THIS PAGE: Sharp, Paula and Ross Eatman. "Andrena." Wild Bees of the National Butterfly Center of Mission, Texas. 15 Jan. 2019, http://www.wildbeestexas.com. Accessed [day/month/year guide accessed].