Tom Turpin
Professor of
Purdue University







Uninvited Winter Guests of the Insect Kind

The last warm days of fall bring a multitude of uninvited guests to Midwestern homes. And we're not talking relatives who have arrived to enjoy the beauty of fall colors of hardwood trees. We're talking insects. Sometimes lots and lots of crawling insects!

Yes, much to the concern of many homeowners, fall brings more than leaves to rake. It brings insects seeking to shelter themselves from the upcoming winter by moving into our homes.

So who are these interlopers? Insects that hibernate, that's who. Some insects are like other hibernating animals, they spend the winter as adults in a state of suspended animation. 

Most insect hibernators seek shelter in natural places—under a rock or the bark of a tree, for instance. Some just crawl into the leaf litter to gain a little protection from the winter.

A few insects avail themselves of our homes for a long winter's nap. These freeloaders include a beetle, a bug or two, a fly and a wasp.

We are all too familiar with the Asian ladybugs that have inundated some homes. These orange beetles are sometimes called Halloween beetles, not only because of their color but because they show up in large numbers about this time of year. While many species of ladybugs look for protected places to overwinter, the Asian type is really aggressive about seeking structures to hide in during the winter.

The Asian ladybug populations have reached very high numbers in recent years. This has meant that thousands of the insects congregate on the south side of some homes as they seek to find a way inside. If they happen to get into the wall spaces or the attic, there is a chance they will remain there until later in the spring. A chance, that is. Sometimes the heat from the house will be enough to keep them active, and they will find their way into the living quarters. This, of course, doesn't sit well with homeowners who prefer insect-free houses.

There are also some real bugs that end up in our homes during the fall. These true bugs, members of the insect order Hemiptera, include the red-and-black bug known as the boxelder bug. These brightly colored bugs feed on the seeds of boxelder and ash trees. Come fall, they, like the ladybugs, seek protected places for the winter. It is not uncommon to see great clusters of the boxelder bugs hanging on the sunny side of the house.

Three other bugs that sometimes invade our home are leaf-footed bugs, squash bugs and stink bugs. All of these home-invading bugs share a common attribute with the aptly named stink bug: They produce an offensive odor. So, if you pick up these insects in your hands, you get stinky. The ladybugs also produce an odor when handled.

The stable fly and the cluster fly overwinter in the adult stage. These flies may end up in a house as they seek shelter. Of the two, the cluster fly is the most commonly observed in homes. Cluster flies look very much like the common house fly but have a different lifestyle. Cluster flies are parasites of earthworms.

Another fall invader is the paper wasp queen. Wasp queens look for cozy places to overwinter, and some manage to find their way into our homes. They generally won't sting, but it is somewhat frightening for folks to find a wasp flying around in the house during the fall and winter months.

Few of us welcome these insects into our homes for the winter. We seem to the like the idea of winter months that are insect free!


Writer: Tom Turpin
Editor: Olivia Maddox