Mining bees, from the genus Andrena, are a huge group of bees that nest in the ground. There are over 1,300 species and they are all solitary bees. Once the female has mated in early spring, she builds a nest in the ground, and then takes care of the eggs by providing pollen and nectar. There might be many females in a small area but each one is doing all the work by herself in her own nest.
The eggs laid by the females will hatch and, over the course of the summer, grow to a pre-pupal stage. They will then remain underground in the nest until early spring when they emerge as adults. After mating, the new females will build nests and start the cycle all over again.
Many of the Andrena bees are monolectic, meaning they collect pollen from only one species of plant. This makes them critical for that species, and vice versa. If either the bee or the plant becomes rare or extinct, then they both face extinction.
These are typically small bees, around 8-17 mm long. The females have a velvety patch of hair between the eyes and the bases of the antenna. They have well-developed pollen gathering baskets, known as corbiculae, on their hind legs and the sides of their thorax. Males are smaller and less hairy than the females.
Look for Mining bees on early blooming trees, such as the Chokecherry shown above, and shrubs like New Mexico Olive (Forestiera) and Gooseberries. They are really important for pollination of early bloomers.
Profile by Dana Ecelberger