Every few days I have a new favorite bee, and today the light of my life is Andrena prunorum. I just received positive identification from John Ascher (founder of the American Museum of Natural History Bee Database) so I don’t have to say I think it is Andrena prunorum; it just is.
From a short distance, I mistook this bee for a honey bee holding her wings at an odd angle. She was working the blackberries along with the honey bees and was roughly the same size. But on closer inspection, I saw orange legs and a hairy face—not so honey beeish after all.
The genus Andrena is large, containing about 1300 species, many of which occur here in North America. Collectively known as mining bees, the Andrena are solitary ground nesters that sometimes live in groups. Many of the Andrena are oligolectic, meaning they forage on only one—or several closely related—species of plant.
Like some other ground-nesting bees, many Andrena females have pygidial plates at the tip of their abdomens. The plate is used like a spatula to spread waterproof secretions from her body over the inside of her burrow and egg chambers.
Another feature commonly found in Andrena is a pair of basitibial plates at the top of the tibia near the femur. You can think of these pointed plates as crampons for bees’ knees. By planting these plates into the sides of her burrow, she can brace herself for further excavation. They also help her climb vertical tunnels up to the soil surface.
In addition to the above, Andrena have characteristics unique to the genus:
- They have velvety patches between their large compound eyes and the bases of the antennae.
- They have propodeal corbiculae. These corbiculae are much like those found on the legs of honey bees except they are located just behind the propodeum, in the space between the thorax and the abdomen. Sometimes they are called “saddle bags.”
- They also have very long hairs on the hind legs for pollen collection.
The species I photographed, A. prunorum, is known as an excellent pollinator of apple trees. I saw her on a blackberry, which makes sense for an oligolectic bee since both plants are in the same family, Rosaceae.
Such a beautiful bee! And right in my own backyard . . .