Digger bees visit a wide variety of flowers and are important in pollination. They’re also called longhorned bees due to the exceptionally long antennae of the males.
Digger bees range from the size of a Honey Bee to as large as a bumble bee. These bees mostly nest in the ground and line their brood cells (compartments for offspring) with a waxlike secretion. In some species, the females construct a characteristic turret, a chimneylike extension of the nest entrance.
Other digger bees nest in wood and some are parasites of other bees. Parasitic digger bees do not construct nests.
Digger bees display very intriguing nesting and foraging behavior. Many species nest in dense aggregations, and swarms of males cruise around the nesting sites searching for emerging females. In one species, the males can detect the females in the ground before they emerge.
These males dig a hole into the ground where the female will emerge and then await her arrival. Other males try to take over and fights ensue. The largest bee usually wins.
A species of digger bee called the southeastern blueberry bee specializes on blueberry plants in its pollen-collecting. It’s more efficient at pollinating these plants than Honey Bees or bumble bees. Another species, the pallid bee, puts on spectacular displays of mating behavior in the spring around nests in desert washes in Arizona.
The Pacific sand dune bee is a digger bee that nests in coastal sand dunes in California, Oregon, and Washington. The females dig nests 0.9 m (3 ft) deep in compacted dune sand.