Native Bee Roundup: Solitary Bees

Carpenter Bee

• Along with bumble bee queens, carpenter bees (genus Xylocopa) are the largest native bees in the United States. There are numerous species of carpenter bees that inhabit a broad range of ecosystems from tropical to subtropical to temperate.

• They get their name from their habit of excavating precisely rounded galleries inside wood. Using their broad, strong mandibles (jaws), they chew into dead but non-decayed limbs or trunks of standing dead trees. Some species also occasionally take up residence in fence posts or structural timbers, especially redwood, and can become a minor nuisance.

• Inside their galleries, the female creates separate cells using sawdust and saliva, and rears one larva in each. Males serve as guards to the nest, often hovering loudly and “dive-bombing” interlopers. But don’t be alarmed—male carpenter bees cannot sting. Only females can, and will only do so if manhandled.

• While we may know them as a pest species, carpenter bees are incredibly important to our environment.

Leafcutter Bee

• Leafcutter bees mate shortly after emerging in the spring. The males live for a short period of time after mating, whereas the females seek out potential nesting sites. 

• They use cut leaves to construct nests in cavities (mostly in rotting wood). They create multiple cells in the nest, each with a single larva and pollen for the larva to eat.

• Some leafcutter bees are even used as commercial pollinators (like honey bees) in crops such as alfalfa and blueberries.

• Leafcutter bees use 0.25- to 0.5-inch circular pieces of leaves they neatly cut from plants to construct nests. They construct cigar-like nests that contain several cells. Each cell contains a ball or loaf of stored pollen and a single egg, which produces a single bee.

• When the larvae emerge, they feed on the food in the nest and pupate over winter. In spring, the new generation of adult bees chew their way out of the nest and the lifecycle begins anew.

• Leafcutters do not aggressively defend nesting sites like honey or bumble bees. Their sting has been described as far less painful than that of a honey bee. Leafcutter bees will only sting if handled.

Photo courtesy Megan Houle/USFWS