How come some types of insects like cockroaches always seem to be found in the kitchen while other bugs are only in the basement, or in the bathroom? How come we don’t have insects in the bedroom for instance? J. O., Saugus, MA

Like other animals, insects require three things – food, water, and shelter. They look for a location that will provide all three. As with all animals though, the need for food generally outweighs the others. If you know what certain insects feed on, you can pretty much predict where they will be found in a home.

For example, the number one site for German cockroaches is kitchens because that is where the food and the food spills are found. It’s also nice and warm, they like that. Why would they want to hang out in a bedroom instead? And for pests that feed on stored foods, such as flour beetles or grain moths, the kitchen is again the obvious and maybe only place to be.

DAMPNESS IS IMPORTANT FOR INSECTS, TOO

Camel cricket. Shuttersock

After food, the second priority for many insects is moisture. Insects may not drink water but they require high humidity in the air. Insects dry out easily and die in conditions of low humidity so they gravitate to bathrooms, basements, and laundry rooms that are damp or where there may be water leaks. Some typical pests that need the high humidity are sowbugs, pillbugs, millipedes, camel crickets, fungus beetles, and springtails. One insect, the drain fly, lives in the scummy residue found down inside sink, shower/tub, or floor drains. It wouldn’t easily survive away from drains.

SOME INSECTS ACTUALLY PREFER BEDROOMS

As far as insects in the bedroom, they are there (or they can be). They are just not your usual pests and they are very good at hiding. There is at least one insect that specializes in bedrooms – our nemesis, the bed bug. Why? Again, think about the requirement for food. The bedroom is one place where the bug can consistently find its food, human blood, provided by a docile sleeping victim that isn’t going to fight back. A bed bug wouldn’t do very well if it set up housekeeping in a busy kitchen.

There are other insects that also find their food source in a bedroom. Clothes moths or carpet beetles may be hidden in closets or dressers feeding on woolens and other stored fabrics. If you have kids that eat in bed, you have extended the possibilities for bedroom pests even further.

LOCATION RULES ARE MADE TO BE BROKEN

House centipede hunting at sink drain. Shutterstock

When each insect has its own favorite food types and its own favorite habitat, competition is reduced, and multiple pest species can coexist in your home together. But if you have a heavy infestation of any insect, all bets are off as far as its location. When competition gets tight or if food becomes scarce, insects will be forced out into less desirable locations and may be found in unusual sites. But don’t worry, predatory insects, spiders, or carnivorous centipedes don’t really follow location rules and can be found anywhere that their prey insects are found.