Spring is here! And with it, a new season of bees. Honey bees, having spent the winter clustered for warmth and feeding on honey stored from the previous year, are well adapted to take advantage of the earliest of blooms on sunny days, especially with the disconcertingly dry winter we've had in the Rogue Valley. Bumble bee queens are also out and about looking for potential nest sites, and looking for nectar to replenish them after their long winter dormancy. Despite the widespread recognition by the lay observer of the honey bees and bumble bees, the most speciose group of early spring bees are the mining bees in the genus Andrena.
|Andrena males on Polemoneum carneum near Pilot Rock (Ashland, OR)|
|Two different sized Andrena females on Ceanothus integerrimus|
|Andrena pertristis (?) on common dandelion|
|Male Andrena perched on Fritillaria affinis, near Pilot Rock|
|Andrena on February blooming Scilla mischtschenkoana in my garden|
|Lomatium californicum on Upper Table Rock with swarming male Andrena|
Andrena are short tongued bees, and most forage for nectar on flowers with easily accessible nectar. Unlike honey bees and bumble bees which use their proboscis more like a straw, short tongued bees lap up nectar not unlike a cat. This doesn't mean all Andrena can't access nectar in larger or deeper flowers, some species have longer mouth parts or special adaptations that enable them to reach hidden nectar. Many species are pollen specialists and only collect pollen from a narrow range of plant species. For example, some Andrena species only collect pollen from Asteraceae (sunflower family), Apiaceae (parsley family), or willows (Salix spp.). The specialists will still collect nectar from a wider range of plants, including many nonnative plants. Most species aren't terribly picky, and some are important pollinators of cultivated plants in gardens and agricultural settings, though mining bees aren't commercially managed like alfalfa leafcutter bees or orchard mason bees.
|Male Andrena with extended proboscis|
|Plum blossoms with an Andrena male|
|Female Andrena with pollen laden scopae|
|Male nectar thief stealing nectar from a slit in the side of a manzanita flower.|
|Lasthenia californica ssp. californica and male Andrena on Upper Table Rock|
|Fritillaria affinis with possible Andrena pollinator?|
|Andrena female gathering pollen on oak catkins, I was very excited to capture this photo!|
|Nomad cuckoo bee (Nomada)|
Danforth, Bryan. The Solitary Bees: Biology, Evolution, Conservation. 1st ed., Princeton University Press, 2019.Fowler, J. (2020). Pollen Specialist Bees of the Western United States. https://jarrodfowler.com/pollen_specialist.html
Michener, Charles. The Bees of the World. 2nd ed., Johns Hopkins University Press, 2007.
Miliczky, Eugene. “Observations on the Nesting Biology of Andrena (Plastandrena) Prunorum Cockerell in Washington State (Hymenoptera: Andrenidae).” Journal of the Kansas Entomological Society, vol. 81, no. 2, 2008, pp. 110–21.
O’Toole, Christopher. Bees: A Natural History. First Edition, Firefly Books, 2013.
Stephen, William Procuronoff, et al. The Biology and External Morphology of Bees. Amsterdam University Press, 1969.
Tang, Ju, et al. “Pollinator Effectiveness and Importance between Female and Male Mining Bee (Andrena).” Biology Letters, vol. 15, no. 10, 2019, p. 20190479.
Wilson, Joseph, and Olivia Messinger Carril. The Bees in Your Backyard: A Guide to North America’s Bees. Princeton University Press, 2015.