Paper Wasp

Polistes species

How do you recognize a paper wasp and its comb?

By the shape of the nest, which is unlike anything else built locally, and by what the insect does with its legs.

The comb. A paper wasp nest is a single layer of open hexagonal cells, gray and papery, hanging downward from a short stalk attached to an overhead surface. There is no envelope, no covering and nothing hidden — you can see straight into the cells, and the adults sit on the face of the comb with their heads outward. A well-established nest reaches roughly the size of a hand. Cells that have produced adults are capped or empty; cells in use hold pale larvae you can see if you look. It looks like a small fragment of honeycomb suspended from a stalk, and once you have seen one you will never mistake it for anything else.

Compare that with the alternatives. A bald-faced hornet builds a large closed gray envelope with a single guarded hole near the bottom. An eastern yellowjacket builds the same enclosed architecture but inside a hole where you cannot see it at all. The paper wasp is the only one of the three that leaves its work in plain view.

The insect. Longer and more slender than a yellowjacket, with a narrow waist and an abdomen that tapers at both ends into a spindle shape. The native species here are generally dark — brown, reddish-brown or black — with yellow markings, and they vary. The reliable field mark is the flight: a paper wasp lets its long hind legs dangle below the body and moves with a slow, drifting quality, whereas a yellowjacket tucks its legs in tight and flies fast and directly. From a deck chair, that difference is visible at ten feet.

What it is doing there. Paper wasps are predators. Adults hunt caterpillars and other soft-bodied insects, chew them and feed them to the larvae, and the adults themselves take nectar and sugars. A colony working a yard through the summer removes a genuinely useful quantity of leaf-feeding caterpillars, which is a reason to be selective about which nests you remove.

Why does the European paper wasp change the diagnosis?

Because one member of this group behaves like a cavity nester, looks like a yellowjacket, and is now common across this region.

The European paper wasp, Polistes dominula, has been established in the Northeast for some years and is widespread on Long Island and in the city. It is boldly marked in yellow and black in a way that looks convincingly like a yellowjacket at a glance, and it is the reason a lot of “yellowjacket” calls turn out to be something else. The quickest way to separate them is the antennae: on the European paper wasp they are orange, while a yellowjacket’s are black. The dangling-leg flight profile still applies, and the body remains the slender paper wasp shape rather than the compact yellowjacket one.

The behavioral difference matters more than the appearance. Native paper wasps want a sheltered overhead surface in the open. The European species will happily do that too, and it will also build inside small enclosed spaces the natives largely ignore: the hollow interior of a metal deck or porch rail, the open end of a pipe rail, a hollow fence post, the burner tubes of a gas grill that has not been used since last year, a wall-mounted mailbox, an electrical meter enclosure, a birdhouse, a downspout mouth, a piece of stored furniture, the cavity in a concrete block, and small voids around window casings and shutters.

It also gets started earlier in the season and builds up faster, so a European paper wasp colony is often further along in June than a native colony is.

The practical consequence is a diagnostic one. If somebody reports wasps going into a small hole in a rail or a post, the question is whether this is a small open comb inside a tube — in which case the work is contained and straightforward — or a genuine yellowjacket colony expanding into a framing bay, which is an entirely different scope. The answer comes from watching the traffic and looking at the insects, and it is worth taking the time to get right, because the two jobs are not comparable in size.

Where do they build on a house, and what makes a surface attractive?

Overhead, sheltered from rain, with clear air beneath the comb — and there are more such places on a house than anyone realizes until they go looking.

The reliable locations. The underside of a porch or a covered entry ceiling. The top corner of a door frame, particularly a storm door or a screen door. The head of a window casing, and behind a shutter. Under the eaves and inside soffit returns. The underside of a deck rail, and the framing beneath a deck. Inside an open garage or carport, on the ceiling or in an upper corner. The interior of a shed or an outbuilding. Under a barbecue lid or on the underside of a table. Inside a rarely opened mailbox. On a light fixture or under its shade. Under an arbor, a pergola, a playset platform or a patio umbrella left furled. In a hanging plant that does not get watered often enough. Under the lip of a gutter, and inside a downspout mouth.

What they have in common. A horizontal or steeply sloping overhead surface, protection from direct rain, some shading, an unobstructed approach so the adults can land and take off, and freedom from routine disturbance. That last condition is why the objects that get used are so often the ones nobody moves: the spare grill, the folded umbrella, the stack of chairs at the side of the garage, the shed that gets opened twice a year.

Why the position determines whether it is a problem. A comb of a few dozen wasps in the corner of an unused shed is not a hazard. The same comb on the head of a back door frame is, because every time the door closes the whole assembly vibrates and the colony is provoked directly above the person standing in it. Nests on rails are a similar case: the wasps are inoffensive until somebody’s hand lands on the timber six inches from the comb.

This is also where the difference from cavity-nesting species shows up structurally. A yellowjacket problem is about a gap leading into a void, so the fix is sealing. A paper wasp problem is about an exposed sheltered surface, which you generally cannot seal away — you can only manage it, keep the used areas clear, and close the tubular and enclosed elements that the European species exploits. Different problem, different intervention.

What is the colony year, and where do the wasps go in winter?

An annual colony that stays small, and a winter population that spends the cold months inside your building.

Spring. Mated females that overwintered emerge and look for a site. A paper wasp colony is often founded by more than one female working together, with a dominance hierarchy establishing which of them becomes the egg-layer while the others forage and build. She — or they — construct the stalk, add the first cells, and raise the first brood without help.

Early summer. The first workers emerge and take over hunting and building. The comb grows cell by cell in a roughly circular expansion. Colonies stay small compared with the cavity nesters: a mature paper wasp nest supports dozens of individuals rather than thousands, and that single fact keeps the risk profile modest.

High summer. Peak activity. Hunting is heaviest, which is when the colony is doing the most good in a vegetable garden. The comb reaches its full size, and adults cluster densely on its face.

Late summer. The colony produces next year’s reproductives. Foraging shifts toward sugars, though paper wasps are far less inclined to scavenge at bins and picnic tables than yellowjackets are — they are a yard insect rather than a barbecue insect, and that difference is noticeable.

Autumn — and this is the part that concerns the building. New mated females leave the nest and look for somewhere sheltered and frost-protected to spend the winter. Very often that is the structure. They tuck into unheated attic corners, gable louvers, the gaps behind fascia and trim, the space behind shutters, wall voids, hollow columns, sheds, detached garages and the cavities around window frames. They do not feed and they do not build; they simply sit it out.

Winter. A mild spell warms the void they are in, rouses them, and they move toward light and warmth — which frequently means the wrong side of an upstairs window, an attic light, or a recessed fitting. This is the origin of the very common report of a large slow wasp on a windowsill in February, and it is a building diagnosis rather than a wasp problem: it means there is a route from that void into the living space, and the same route is available to everything else. The cluster fly profile covers the identical mechanism with a different insect, and the two are regularly found on the same windowsill.

The founding females and the entire worker force die with sustained cold. The comb is finished and will not be occupied again, though a new colony may be founded close to it the following spring.

How much of a risk is a paper wasp, really?

Lower than its reputation, provided you are honest about where the nest is.

Paper wasps defend a much smaller radius than yellowjackets or bald-faced hornets, and they generally tolerate people passing beneath the comb without reacting. The colony is small, so a defensive response involves a few insects rather than a coordinated mass. Most encounters with a paper wasp nest end with nothing happening at all.

What provokes them is contact and vibration at the nest itself, or at the surface it is attached to. That is why the incidents cluster around a specific short list of situations.

A nest on a door frame head. Every time the door closes, the assembly shakes. People walk through the defended zone several times a day, often with their hands full and their heads at exactly the wrong height.

A nest on or under a rail. Somebody grips the rail on a stair and their hand lands beside the comb.

A nest inside a mailbox, a grill or a stored object. The nest is invisible until the object is opened, and the person opening it has their face at close range.

Working overhead. Painting, gutter clearing, window cleaning, hanging lights or setting a ladder against an eave puts a person at arm’s length from a comb they had not noticed.

Ladder falls, which is the injury that actually sends people to hospital. Someone stung while at height reacts, and the fall is the damage. That is the strongest single argument against improvising with a can from a hardware store while balanced on a rung.

Allergy changes everything and is not proportional to the number of stings. Anyone with a known venom allergy should be well clear of the work and should have their prescribed medication accessible. Anything further than that is a question for a physician, not for us. Stings around the mouth or throat are dangerous regardless of allergy status.

And like other wasps, a paper wasp does not lose the sting and can deliver repeatedly.

What are the signs, including the ones that are not the nest?

The comb is usually the first thing seen, but three other indicators will find one you have missed.

Rasped patches on weathered wood. Paper wasps build with wood fiber shaved off bare, weathered timber and chewed to pulp. Look for shallow, pale, streaked grooves on fence rails, deck boards, shed walls, unpainted siding and old garden furniture. Fresh rasping means a colony within a fairly short distance.

Slow, low, dangling-legged flight along a fixed route. Follow it. Paper wasps do not travel far, and a wasp working the same corner of a yard repeatedly is coming from something close by.

Traffic at a small opening in a tubular element. Wasps entering and leaving the open end of a rail, a fence post, a downspout mouth or a grill burner. That is the European species and it is worth confirming, because a small enclosed nest is a contained job and a yellowjacket colony in a wall is not.

Overwintering adults indoors on mild winter days. Large, slow, torpid wasps at upstairs windows, in an attic, at a light fitting, or falling out of a curtain when it is drawn. This tells you where next spring’s foundresses are living and it identifies an envelope gap.

Sound. A rasping, scratching noise from inside a hollow rail or post on a warm day, produced by adults working inside the cavity.

A nest you can see from below. Get in the habit of looking up in spring: door heads, porch ceilings, soffit corners, deck framing, playsets. A comb the size of a coin in May is one insect and no risk at all.

When should a nest be left alone?

More often than the industry admits, and this species is the strongest case for it.

A paper wasp colony is small, it is a genuinely useful predator of garden caterpillars, it does not scavenge aggressively around food and bins, and it will be dead by winter regardless of what anyone does. If a comb is in a location nobody goes — the back corner of a shed that opens twice a year, under a deck that has no headroom, on the wall of an outbuilding at the far end of a property, inside a garage rafter where nothing is stored — then removing it costs you money and costs the yard a working predator.

The honest test is simple. Is the nest within reach of a route people use daily? Is it above a door, a walkway, a stair, a play area, a work surface, a seating area or a window that gets opened? Is it inside something someone will open without warning? Is it on a surface that gets vibrated? Does anyone in the household have a venom allergy? Is there work planned nearby — painting, gutters, siding, roofing — that will put a person at that height? If the answer to all of those is no, the reasonable recommendation is to leave it, note where it is, and take the empty comb down in the winter.

That is not a way of avoiding work. It is the same reasoning we apply to a hornet nest high in a tree at the back of a wooded lot, and it is one of the more useful things a building-oriented practice can tell a homeowner.

How is a paper wasp nest dealt with?

Quickly and simply when it is exposed, and as a small cavity job when it is not.

Exposed combs are the straightforward case. Work is done at dusk or after dark, when the adults are on the nest rather than out foraging, from a stable position rather than at arm’s length off a ladder. The colony is neutralised, then the comb and its stalk are removed and disposed of, and the attachment point is cleaned so there is no residual stalk left on the surface. On a door frame, a porch ceiling or a rail, that is generally the whole of the work.

Cavity nests — the European species inside a rail, a post, a pipe end, a grill or a mailbox — are treated at the opening rather than opened up, for the same reason any concealed colony is. Then the tube gets capped or plugged permanently, which is the part that stops it recurring.

Nests inside stored objects get handled by treating the object where it stands rather than by moving it, which is the usual homeowner mistake.

A note on timing within the season. Removing an exposed comb early in the summer often results in a rebuild nearby, because the founding female survives the removal of an unattended nest and simply starts again a few feet away. That is not a reason to leave a nest above a door; it is a reason to expect a follow-up look, and a reason why the autumn and winter sealing work matters more than the summer removal does.

And if it turns out to be honey bees, which occasionally happens with a colony in a soffit or a wall, that is not a wasp job. Honey bees are not treated as a pest, and a colony in a structure is a beekeeping and removal matter with its own complications — abandoned comb and honey left in a cavity ferments, stains through and attracts a long succession of secondary pests. We will say so and point you to the right kind of help.

What building work reduces next year’s nests?

Close the tubes, close the winter harborage, and walk the property in spring.

Cap every open tubular element. Hollow rail ends, pipe rails, fence post tops, the open ends of scaffold-style hand rails, unused sleeve anchors, downspout mouths, and the burner tubes of a grill that lives outdoors. This is the single most effective piece of prevention against the European species and it is a morning’s work with a bag of caps and some sealant.

Close the autumn harborage. Gable louvers rescreened from behind in metal. Soffit returns properly closed. Fascia and trim gaps sealed. Shutters secured so there is no void behind them. Attic access hatches gasketed. Window casing gaps sealed. Weep holes screened rather than filled. This reduces the number of foundresses that survive the winter in your building, it stops the winter windowsill problem, and it is the same list that keeps out mice, cluster flies and everything else — which is why it is worth scoping as one piece of work under structural exclusion.

Manage the objects. Store the grill covered and check the burners before first use. Keep the folded umbrella and the stacked furniture where they get moved occasionally. Open the shed periodically in spring. Check the mailbox interior. Empty and invert anything that has been sitting since last summer.

Walk the overhead surfaces in late spring with a flashlight and look at the door heads, porch ceilings, soffit corners, deck framing and playsets. A founding nest at that stage takes seconds to deal with.

And take the old combs down in the winter. They will not be reused, but removing them makes next spring’s inspection far easier, because anything you find then is new.

Related work

Method, timing and the sealing work that follows are covered under wasp and hornet removal, the parent service for this profile.

Among the other stinging insects here, the bald-faced hornet is the large aerial species whose nest is a closed envelope rather than an open comb, and it defends far more vigorously. The eastern yellowjacket is the cavity nester whose colony you cannot see and whose entrance must never be blocked while it is active. And the carpenter bee is not a social wasp at all — a solitary insect that bores its own gallery into bare softwood and causes cumulative damage to fascia, rails and pergolas rather than presenting any real sting risk.

If you have a comb above a door or a rail and would rather it was not there, tell us where it is and how high, and if you are seeing slow wasps at upstairs windows in winter, mention that too — it points at a different piece of work. The areas we cover are listed under locations.

Treatment for this pest is covered under Wasp & Hornet Removal.