As humans, we make a lot of assumptions about the bugs that live in our dwellings, but we don't have much evidence as to what's there and why.

A study released Friday in Scientific Reports aims to change that. Researchers collected specimens of arthropods from 50 urban homes in Raleigh, N.C., to see whether the physical aspects of your home—from number of floors and doors to whether you're a slob—correlates to the diversity of the bug population you're hosting. Arthropods, by the way, are any invertebrate animal with segments, which includes insects and spiders.

"It’s not possible that your house will be devoid of arthropods," says Dr. Michelle Trautwein, the study's senior author and the California Academy of Science's Schlinger Chair of Diptera who has also inspected homes in San Francisco, Peru, Australia, Japan, and Sweden. "We build houses and insects and spiders see our houses as an extention of their habitat. Humans create a distinct place for these animals to live."

Bugs in a Rug

It may or may not surprise you, but the researchers found that rooms with carpet host more of our crawly friends than non-carpeted rooms. Big rooms with lots of windows and doors will have a wider variety of specimens. The more floors your home has, the narrower assortment you’re likely to find the higher up you go.

The study also notes that rooms with a greater amount of biodiversity might be healthier for humans, in a roundabout way—exposing you to more germs. That doesn’t mean you should run out and buy wall-to-wall carpet anytime soon.

“Carpeted rooms are not necessarily more healthy,” says Trautwein. “Carpets can create other allergenic problems.”

Indeed, carpet can be a breeding ground for certain pests, such as termites, fleas, or bed bugs (which the researchers found to be relatively rare).

“Carpet is particularly problematic because flea feces fall down into the fibers, and then the larvae feeds on that,” notes CR senior scientist Michael Hansen, Ph.D., a biologist and ecologist who wrote his doctoral thesis on integrated pest management. “In that case you just need to steam clean carpets.”



What may surprise you is that researchers found no meaningful correlation between tidiness and arthropod diversity. In other words, being slovenly doesn't necessarily attract bugs. Whether you have pets also didn't make much of a difference. And neither did the use of pesticides.

More on Home Invaders

“There are obviously some arthropod groups that we would rather not have that can cause structural or economic damage, but there are also tiny predators and scavengers that provide tidying and pest control services free of charge,” says Misha Leong, lead author and postdoctoral researcher at the California Academy of Sciences. “It's also possible that having greater diversity may suppress pest outbreaks from occurring.”

Though it may be hard to accept, the researchers point out that the best way to go about dealing with arthropods in your home may be to accept that they've always been around—and they'll always be around.

“Knowing that the arthropods are there and in pretty much every room in everyone's homes should lead to a cultural shift from people freaking out about bugs to understanding that their presence is perfectly normal and for the most part harmless,” says Leong. “Less pesticide application indoors for non-threatening arthropods would be a good thing overall.”