Andrena are early risers, and this year I was very luck you witness the emergence of a very large aggregation of these solitary bees in Highlands Ranch!
Andrena bees are solitary bees who happily live next door to many other solitary nesters. Some bees in this family will begin their season early spring, as is the case with these mining bees. Others will begin late summer, hoping to visit many of the sunflower family plants.
Andrena can be social or solitary, depending on the weather conditions. They can live in large aggregations, which is like a large housing development for humans. This seemed to be the case with this group, however they can also live in a social structure with one queen laying all the eggs, and workers collecting all the necessary resources.
To identify the nesting hole of Andrena bees, you must be very observant of the smallest of details. The following pictures show mounds of sandy soil, with and without holes. This is evidence of some kind of ground burrowing bee. The mounds without holes are either finished, and full of developing bees, or the mother bee has decided to close up shop and get some rest. They will use dirt, plant debris, petals, or any kind of small covering to cover the holes.
It can be alarming to stumble upon the activity of a large aggregation, however, there is no cause for concern. These bees are too busy to concern themselves with humans or other animals, so long as there is no threat. A perceived threat would be digging into their nesting site, or grabbing a bee out of pure harassment. Wouldn’t you sting something if you felt threatened? I sure would, and sometimes I wish I could sting to get the “point” across…he,he.
Andrena are of the few early rising bees, and that means the few flowering plants that are also early bloomers depend on these bees for their pollinating services. So, consider yourself pretty darn lucky when you have been chosen to host these tiny ladies on your property. Sit back and enjoy the very busy show.
Thank you for joining the movement!
Look at all that pollen! She’s covered in yellow dust.