Other Common Names
Known simply as the black carpenter ant in the East and Midwest, I suggest prefacing with "Eastern" to distinguish from C. modoc.
Explanation of Names
Camponotus pennsylvanicus (De Geer, 1773)
6-7 mm smallest minor worker
12-14 mm large major worker
15-18 mm queen
Broadleaf and mixed forests (both floodplain and upland), woodlands, tree-studded parks, cemeteries, and lawns. The nest is in dead, usually already rotten wood. Occasionally nest in wooden buildings, typically where wet or dry rot has softened the wood. Probably increasing in numbers and distribution in the West due to extensive tree planting in the Plains.
Workers active throughout the warm part of the year, dormant and torpid in winter, even when warmed up.
Sweets and protein, acquired from extrafloral nectaries, honeydew of aphids and hoppers, and scavenging or hunting soft-bodied insects.
Mating flights are usually on the first warm humid afternoons in spring, but alates are reared in late summer and a few may fly in fall in a small nest under bark of a rotten log, usually on the forest floor, but sometimes in a dead limb or gall in a tree. Mated queens rear the first brood of 3-10 small workers during the summer following spring matign flights. Those that fly in fall apparently do not survive. Mature colonies may live for 15 or more years, and may become essentially immortal by adding queens in peripheral portions of arboreal nests after mating flights.
Click on the image below for a series showing Black Carpenter Ants attacking a Citronella Ant nest.
"C. herculeanus is very similar, but with dark red propodaeum and legs, and a less showy golden pubescence on the "abdomen" (metasoma)." -- Richard Vernier
C. herculeanus is, however, a more northern species, with most of its range in Canada. -- added by James Trager