Carpenter Bees

Xylocopa Spp.

Description: Carpenter bees get their common name from their habit of boring into wood to make galleries for the rearing of young. These are worldwide in distribution with 7 species occurring in the United States.

Habits: Females of the carpenter bee will nest in a wide range of woods, but prefer weathered and unpainted wood. Valley carpenter bees prefer partially decayed live oak, deciduous oak, eucalyptus, and other hardwoods. The Mountain carpenter bee is recorded as nesting in structural timbers.

Male carpenter bees tend to be territorial and often become aggressive when humans approach, sometimes hovering a short distance in front of the face or buzzing one’s head. Since males have no stinger, these actions are merely show. However, the female does have a potent sting, which is rarely used.

Cicada killer

Sphecius speciosus

Description: The wasp gets its common name from the fact that it hunts and provisions each of tis nest cells with a cicada as food for its young. These wasps can become an urban nuisance pest when they select a bare area around a structure as a nesting site. People become alarmed because they look like giant yellowjackets. In the United States, they are found east of the Rocky Mountains.

Biology: Cicada killers are solitary wasps, do not live in colonies or nests. The female locates a cicada, stings it, and brings the paralyzed cicada back to the burrow. One or 2 cicadas may be placed in each burrow and an egg is deposited on one. The wasp larva feeds on the paralyzed cicada. Full-grown larvae overwinter in their burrow, pupate in the spring, and emerge as adults during the summer, usually in July and August.

Habits: Typically areas of bare ground are used as nesting sites. Many individuals may use the same general area for nesting purposes. While digging their burrow, the females excavate a sizeable pile of soil, which can be disfiguring to a lawn. Females in general will not sting unless handled or stepped on, such as by barefooted children. Males will buzz people but cannot sting.

Baldfaced hornet

Dolichovespula maculata

Description: This atypically large black-and-white yellowjacket gets its common name of baldfaced from its largely black color but mostly white face, and that of hornet because of its large size and aerial nest. Baldfaced hornets are found throughout the United States.

Biology: Baldfaced hornets are social insects, which live in aerial nests. In the spring, the female uses chewed-up cellulose material to build a paper carton nest of several dozen cells covered by a paper envelope. The nest will eventually consist of 3-5 rounded paper combs which are open ventrally and attached one below another, and are covered with a many-layered envelope. One egg is laid in each cell as it is constructed. Nest size varies and contains 100-400 workers at its peak.

Habits: The overwintering queen selects the nest site. This can vary from shrubs or vines at ground level to 66 ft or higher in trees. Nests may also be built on overhangs, utility poles, houses, sheds, or other structures. Nearly all nests are constructed in exposed locations. At maturity, the nests can by quite impressive with sizes of up to 14 inches in diameter and over 24 inches in length.

Mud daubers

Various names

Description: This group of wasps gets its common name from the fact that they construct their nest of mud. They are typically nuisance pests. Mud daubers are found throughout the United States.

Biology: Mud daubers are solitary wasps, they are not social and do not live in colonies. Females construct nests of mud. Each cell is provisioned with several spiders, which she has paralyzed with her venom, with the first spider in having an egg deposited on it.

Habits: Mud daubers typically select a sheltered site to build their mud tubes. Favorite sites include under eaves, porch ceilings, in garages and sheds left open, in barns, protected building walls, in attics, etc. Nests typically exhibit round holes in them as the wasps emerge. This means the nest is probably olf and inactive after springtime.

Paper wasps

Polistes spp.

Description: Paper wasps get their common name from the paperlike material of which the construct their nests; true also of the other vespids. It has been suggested that they be called umbrella wasps based on the shape of their nests. In the urban situation, these usually unaggressive wasps are a nuisance pest. Various species are found throughout the United States.

Biology: Paper wasps are semi-social, existing in small colonies but without a worker caste. Nests consist of a single layer of paperlike comb with the cells opening downward. This comb is supported/suspended from branch, twig, or horizontal surface by a single long pedicel; this single, long pedicel apparently aids in the defense of the nest by predators such as ants. This comb is never enclosed by an envelope but remains naked.

Habits: Paper wasps hang their comb nests from twigs and branches of trees and shrubs which can cause concern when ornamental shrubs and hedges are trimmed or fruit is being picked from trees. If a nest is contacted, there is high probability that the person doing the trimming or fruit picking will get stung. Paper wasps also like to hang their comb nests from porch ceilings, the top member of window and door frames, soffits, eaves, attic rafters, deck floor joists and railings, etc., almost an protected place imaginable.


Vespula spp., Dolichovespula spp.

Description: Yellowjackets receive their common name from their typical black and yellow color pattern. They are worldwide in distribution with about 16 species occurring in the United States.

Biology: Yellowjackets are social insects and live in nests or colonies. In the spring, the queen uses chewed-up cellulose material to build up a paper carton nest of a few cells, which will eventually consist of 30 to 55 cells covered, by paper envelope. Nest sizes vary and usually contain 1,000 to 4,000 workers at its peak.

Habits: Depending on the species, the overwintering queen will usually select either a subterranean or aerial nesting site. Most of the pest species are ground nesting. However, the German yellowjacket usually nests in buildings in the United States and the aerial yellowjacket commonly attaches its nest to shrubs, bushes, houses, garages, sheds, etc. There are nest entrance guards to protect the colon. Yellowjackets are very slow to sting unless the nest entrance is approached and then they are quite aggressive. Each can sting a number of times, inflicting much pain. Some people become hypersensitive to their stings and future stings can become life threatening. Those nesting in or on buildings are only a problem when the nest or nest entrance is located near human activity.