Question

I’ve got wasps inside my house! It’s hardly even spring yet but I’ve seen 5 or 6 large, blackish wasps around my patio doors. Could I possibly have a nest in the house somewhere?

Answer

At this time of year, there are no active wasp nests anywhere. They have yet to be built. What you have are wasps that have been spending the winter in your house (maybe in your attic) and are just now becoming active. You most likely have been playing host to overwintering paper wasp queens. Of all the different wasps, paper wasps are the ones that seem to move into homes in the fall, looking for warm, protected places to hunker down until spring. It’s just the mated queens that are destined to survive the winter; the rest of the wasps died in the fall.

How Did They Get In?

Paper wasps (sometimes called umbrella wasps) are the ones that build those upside-down, umbrella shaped nests around the eaves of our homes, behind shutters, over doorways, or under porch overhangs, inside sheds, or sometimes inside attics. Since their nests are usually associated with our homes already, it’s an easy thing for paper wasps to find a crack or crevice to get inside. Because paper wasps fly, they are able to enter through openings near the roofline and often end up in attics. Most people don’t even notice the gradual fall migration of the wasps inside, although you might notice them hanging around windows and doors, attracted to the warmth. Once inside, they hide in attics or wall voids, or behind baseboards, behind draperies, and in various cracks and crevices.

What Happens Once They’re Inside?

Paper wasps don’t move around much once they’re settled in and you usually won’t even know they’re there—until the first warm days of spring when the wasps “wake up.” The wasps are not so good at finding their way back out through the same opening though, and can wander through the house, looking for a way out. They’re attracted to light at windows which is why you’re finding them around your patio door.

If the paper wasp queens make it back outside, they usually stay near your home while looking for an appropriate nest site. They don’t reuse old nests but they do tend to build their nests in the same sites year after year. The queen begins the comb nest with just a few cells in which she lays eggs. As workers emerge, they take over rearing the young. Unlike large yellowjacket colonies, paper wasp nests remain fairly small, usually less than 100 workers.

What Can I Do?

The presence of a few overwintering paper wasps in a home is a common thing and doesn’t require treatment other than pest-proofing your home (sealing up openings, screening vents, etc.) to keep them out. The wasps are usually sluggish as they crawl and fly around inside, so they can be easily caught, or squashed, or vacuumed. They’re not aggressive but remember that they can sting if handled.

Treating the inside of your home after the wasps have moved in does little good since they are dispersed into so many different hiding places. In the rare case where a home has a lot of overwintering wasps in an attic space, the attic can be sprayed or dusted. If you usually have a lot of paper wasp activity around the outside of your home, we can treat areas where paper wasps have nested before to prevent new nest building. Give Colonial a call–we can also do that pest-proofing for you to keep wasps out next fall.

e_monk / Foter.com / CC BY-NC-SA