Biology and Management
Carpenter bees (Xylocopaspp.) are large and economically important insects that are active from early spring through summer. Like other bees, carpenter bees pollinate crops and home gardens. However, they tend to hover around houses and other wooden structures when searching formates and favorable sites to construct their nests. They almost totally depend on man-made structures for the wood used to construct their nests. Homeowners are often frightened about being attacked by the
carpenter bees that hover erratically around their homes. Homeowners
are also concerned about the holes carpenter bees make in wood, which often lead to more serious damage by woodpeckers whenthey try to feed on the carpenter larvae deep inside the holes. Carpenter bees are not stinging bees like honeybees and bumblebees. A male carpenter bee is aggressive when protecting its nesting site, but is harmless because it does not have a stinger. Although a female has a stinger, will not usually sting unless it is handled or molested.
Identification Among the largest bees, carpenter bees(Figure 1) resemble
bumblebees, Bombus spp.,
(Figure 2) and giant resin bees, Megachile sculpturalis Smith, (Figure 3). All three species of bees have yellow hairs on a black-colored body. Carpenter bees and giant resin bees share more similarities than bumblebees. The giant resin bees are the largest (1 to 1½ inch), followed by carpenter bees (½ to 1 inch), and bumblebees (¹⁄³ to ¾inch).
Carpenter bees and giant resin bees can be distinguished from each other using the following characteristics:
• Carpenter bees excavate their own tunnels; giant resin bees locate and occupy tunnels and holes made by others.
• A carpenter bee has a more robust and heavy body; a giant resin bee has a longer and cylindrical body (Figure 4). Male and female carpenter beeslook different from each other. A male carpenter bee has a white- or cream-colored spot on the head between mandibles and appears to have a white “nose” on the face. A female bee does not have the spot. Most of the congregating bees in the early spring are
males. They hover around waiting for the females and defending their territory. You can completely ignore the males because they are incapableof stinging, although
they will confront you whenever you enter their territory. sawdust underneath freshly
drilled holes. The sawdust is cast out while carpenter bees excavate tunnels. The third sign is the yellow or brown excrement stains on the sides of buildings underneath
entrance holes. Carpenter bees are usually nuisance pests, but can cause considerable structural damage from repeatedcolonization of the same area. Woodpeckers often peck through the wood surface of carpenter bees’ tunnels to prey
on the larvae inside, thus causing more severe damage. be present beneath the entry
hole and burrowing sounds may be heard from within the wood. Normally, the gallery will extend about 4 to 6 inches, but with repeated use, galleries may be
Females lay their eggs withina series of small cells. After completing a tunnel, the female puts a ball of pollen moistened with nectar at the farthest point from the entrance hole and lays an egg on it. She seals off this cell with a thin wall of wood pulp and repeats the process. Eventually, the tunnel is partitioned into as many as four to eight cells. The egg hatches and the larva feeds on the food ball. Interestingly,adult bees emerge from pupae at nearly the same time within a nest, regardless of age. Adults then chew through the wall of the
Because carpenter bees nest in wood, they can cause aesthetic and structural damage. Common nesting sites include house siding, eaves, window trim, fascia boards, shingles, decks, fences, and outdoor furniture. The...