When most people see a bug in their house, they freak out. But according to a new study by researchers North Carolina State University, there’s no reason to fear – because there will be bugs in your house no matter what you do, and this may actually be a good thing.

This graphic shows the proportional diversity of arthropod types across all of the rooms surveyed. Image credit: Bertone, et al.

If you’re reading this at home, look around you. You may not see anything, but you’re probably surrounded by tiny arthropods – tens of or hundreds of them. Matt Bertone and his colleagues wanted to see just how humans and tiny insects co-exist, so they set out to investigate 50 homes within 30 miles of Raleigh, North Carolina. They found that every house had, on average, over 100 different types of insects.

“I saw a lot of things in homes that I had never seen in the wild before, things we’ve previously tried to trap,” Matthew Bertone, an entomologist and lead author of the paper said.

It was the first ever study to quantify the biodiversity of insects in US homes. In total, they searched over 500 rooms, and just 6 of them were insect-free. To be honest, they probably also missed some insects because they never checked underneath carpets and in drawers or cabinets.

“This was exploratory work to help us get an understanding of which arthropods are found in our homes,” says Matt Bertone. “Nobody had done an exhaustive inventory like this one, and we found that our homes host far more biodiversity than most people would expect.”

At this point, something should be pointed out: most of the insects found were completely benign. Ants, midge flies, cobweb spiders, and carpet beetles were the most common species, while cockroach and termites were only found in a handful of rooms.

“The vast majority of the arthropods we found in homes were not pest species,” Bertone says. “They were either peaceful cohabitants – like the cobweb spiders (Theridiidae) found in 65 percent of all rooms sampled – or accidental visitors, like midges and leafhoppers (Cicadellidae).”

A search party of little black ants (Monomorium minimum) finds food on a couch. Photo credit: Matt Bertone.

Furthermore, entomologists believe most of these insects are only short-term visitors.

“While we collected a remarkable diversity of these creatures, we don’t want people to get the impression that all of these species are actually living in everyone’s homes,” Bertone said in a press release. “Because they’re not equipped to live in our homes, they usually die pretty quickly.”

To make things even more interesting, some researchers speculate that not only do these insects not do anything bad – they might actually be useful in our homes. Much like the bacteria in our gut take up space and resources that we don’t need and prevent harmful bacteria from developing, these insects might also be providing environmental services. This is still a rather virgin area of study.

“This is only a first glimpse into the species that live in our homes, and more work needs to be done to flesh this picture out,” says Michelle Trautwein, the Schlinger Chair of Dipterology at CAS and co-author of the paper. “But these insights give us the opportunity delve down into some exciting scientific questions. Now that we have a better idea of which species are most common in homes, we can focus on studying them.

“Do they provide important services that we don’t know about in the ecosystems of our homes? Do any host microbial organisms that affect our health, for good or bad? And we can also begin to explore their traits to see if they share evolutionary characteristics that have made them better suited to live with humans,” Trautwein says.

The paper, “Arthropods of the great indoors: characterizing diversity inside urban and suburban homes,” is published in the journal PeerJ.