Wasps in St. Louis

Wasps, Hornets & Carpenter Bees of St. Louis

Not everything that buzzes is the same — and the difference decides how (and whether) a nest should be treated. Here are the stinging and wood-nesting insects we’re called for most.

Paper Wasp

Polistes spp.

Identify: Slender and long-legged; at rest it folds its wings lengthwise. Its nest is a single open, downward-facing comb — the classic “umbrella” nest with no outer shell.

Life cycle: Nests stay small — rarely over 8 in. across or ~200 wasps. Only mated queens overwinter; a lone founding queen starts each nest in spring and rears the first workers herself.

Habits & risk: Builds under eaves, ledges and porch roofs — right at head height, which is where the conflict starts. A vespid: it stings defensively when the nest is threatened, and venom can trigger a severe allergic reaction in sensitive people.

Yellowjacket

Vespula spp.

Identify: The smallest common vespid, about ½ in., banded bright yellow and black. Same lengthwise wing-fold as other vespids.

Life cycle: Most nest underground, often in an abandoned rodent burrow, or in wall voids; a single-season colony can reach several thousand workers.

Habits & risk: The scavenger at your picnic — it works meats, sweets and trash, and gets worst in late summer and early fall. Many experts consider it the most dangerous social stinging insect in the U.S.; most stings come from disturbing a hidden ground nest.

Baldfaced Hornet

Dolichovespula maculata

Identify: Large and boldly black-and-white (technically an aerial yellowjacket, not a true hornet). Builds the big grey, football / inverted-teardrop paper nest hung in a tree or shrub with one opening near the bottom.

Life cycle: Only mated queens overwinter; a founding queen starts the nest in spring. Nests are never reused — a nest that survives the winter is empty.

Habits & risk: A high, out-of-the-way nest can be left alone; one near a door, deck or walkway needs professional removal. Defensive and capable of repeated, painful stings when the nest is disturbed.

Carpenter Bee

Xylocopa spp.

Identify: Looks like a bumble bee — but the top of the abdomen is bare and shiny black (a bumble bee is fuzzy all over). That glossy back is the giveaway.

Life cycle: A solitary bee: the female bores a near-perfect ½-in. round hole, then tunnels along the grain to build nest cells. One generation a year; it favors bare or weathered softwood.

Habits & risk: The males hover and dart at you aggressively but cannot sting; females can but rarely do. The real problem is years of tunneling in eaves, decks, railings and fascia — cumulative wood damage that woodpeckers often enlarge chasing the larvae.

Identification and biology per Truman’s Scientific Guide to Pest Management Operations, Ch. 10.