Most recently reviewed by: Janet Hurley & Pat Porter (2018)
Common Name(s): Carpenter Bee
Pest LocationUrban Structural
Adult carpenter bees are large (3/4 to 1 inch long) and resemble bumble bees except that the abdomen is hairless and shiny black rather than being covered by patches of orange to yellow hair found on bumble bees. The carpenter bees in the genus, Ceratina, are much smaller (1/4 inch) and are dark bluish-green, and make nests in plant stems.
Carpenter bees are usually shiny or metallic blue-black with a greenish to purplish sheen. Some male carpenter bees have yellow areas on the face, and males of a few species may be partially to entirely buff or pale yellow.
Carpenter bees can be distinguished, however, by the lack of hairs on the top of the abdomen. On the rear legs, female carpenter bees have a dense brush of hairs, whereas female bumble-bees have large pollen baskets.
Origin and Distribution
Adult female carpenter bees can sting but usually only if aggressively disturbed; most carpenter bees “attacking” people passing by nesting sites are territorial males incapable of stinging,
Habitat & Hosts
Structural damage produced by nest-making activities can be somewhat damaging to homes, garages, fences and other buildings, although damage is largely cosmetic unless nesting sites are used repeatedly over years.
They prefer unfinished softwoods such as redwood, cypress, cedar and pine in structures for constructing nests. Carpenter bees do not consume wood like termites, but use wood merely to construct nests. While gathering nectar and pollen carpenter bees pollinate flowers.
Complete metamorphosis. Adults spend the winter in nests constructed the previous year, and become active in April or May. After mating, females construct new nesting tunnels or use pre-existing tunnels. Nesting tunnels are about ½ inch wide and start on the end of wooden beams or at right angles to a surface for ½ to 1 inch before turning and following the wood grain. Tunnels are clean cut and may extend 6 to 8 inches. Females collect pollen and nectar to produce a dough-like mass called “bee bread.” Eggs hatch into larvae that feed on the bee bread in their cells. Development varies with species and temperature, but can progress from egg to adult in a little over a month. There may be two or three generations per year. Continuous generations may occur in south Texas. Adults emerging in late summer or fall do not mate until spring but may gather and store pollen in their tunnels.
Carpenter bee nests are easily distinguished from those of other wood-boring insects. Nest entrances are almost perfectly round and, for the common carpenter bee, about 1/2 inch in diameter. No other insect produces as large an opening with a perfectly round shape.
ManagementIf you live in the State of Texas, contact your local county agent or entomologist for management information. If you live outside of Texas, contact your local extension for management options.
Carpenter bees drill into wooden surfaces such as window sills, wooden siding, eaves, deck railings, outdoor furniture and fences which can be significant. Carpenter bees will attack painted or stained wood surfaces though bare wood is preferred. Carpenter bees do not consume wood like termites, but use wood merely to construct nests.
There are some paint additives that are insecticides, but a less permanent method of control would be to spray the bees with insecticide as they enter or exit the wood surface. Existing tunnels should be filled with stainless steel steel wool and caulk so as to prevent their re-use in the future.
Carpenter Bees. Texas Apiary Inspection Service.