Bees in family Colletidae are called plasterer or polyester bees, and within that group, bees of the genus Colletes are known as ‘cellophane’ bees. They are solitary bees that nest in colonies (aggregations), and they are often first noticed on warm sunny days in spring when the emergence of male bees that fly just inches above ground level. The males are searching for female bees as they dig their way out of the soil.
When females emerge it can sometimes result with her being mobbed by several males, creating a buzzing cluster of chaos.
After mating, female Colletes sp. dig tunnels with small pockets (brood cells) that extend from the sides. Each cell is first lined with a ‘cellophane’ material, which is produced by the bee’s Dufour glands and applied with her short brush-like tongue (glossa) to the walls of the cell. This seals the outside of the cell wall and allows the bee to fill the lower portion with nectar, pollen, and some glandular material. She then lays a single egg above the food and seals the cell with the same cellophane material plus some soil for a cap. She then will go on to dig another cell to repeat the process. When the eggs hatch, the larvae feed on the stored food and then pupate in the fall, to overwinter as adults in the natal cells.
(Photographed on 16 April, 2016, in the Opal Natural Area, Alberta)
– Ecology, Behavior, Pheromones, Parasites and Management of the Sympatric Vernal Bees Colletes inaequalis, C. thoracicus and C. validus. S. W. T. Batra. Journal of the Kansas Entomological Society Vol. 53, No. 3 (Jul., 1980), pp. 509-538.
– Polyester bees: Born in a plastic bag by Patterson Clark. Washington Post, 15 March, 2011.
– Unequal Cellophane Bee, Colletes inaequalis by Heather Holm. Restoring the Landscape with Native Plants, 22 May 2014.
– USGS Bee Inventory and Monitoring Lab–Flikr Photostream.