Last year at this time, I wrote about participating in the Backyard BioBlitz, an event aimed at identifying every species of living thing in your own yard to document its biodiversity. I was thrilled to record nearly 250 species of life in my yard, mostly plants and insects. I even documented a rare orchid hidden among the wetland shrubs in the corner of my property.
But it got me thinking about what I may have missed by only looking for wildlife outside my house. What might I find inside? Surely there would be a few indoor creatures in the nooks and crannies of my house, like spiders in the basement, moths in the birdseed, and maybe even a beetle or two. I know I have mice in the woodpile in the garage.
Then I picked up a book that changed my view of this exercise entirely. "Never Home Alone" by Rob Dunn highlights the research conducted to discover the number of creatures that live inside a typical home. And the results were pretty creepy.
The author, a scientist at North Carolina State University, says he has documented more than 200,000 different species living in homes, mostly in North America. About three quarters of those are bacteria found in dust, water, food and elsewhere. Most of the rest are fungi, with insects, plants and other stuff making up the remainder.
“The species in our homes are a measure of our lives,” he wrote. “The early cave paintings of our ancestors documented the species they watched, stalked and feared. The dust on our walls, in turn, documents the species with which we wake up each day.”
So I wandered around my house to see what I could find. There were definitely cobwebs in the corners of many of my rooms – an indication of my poor housekeeping and also a confirmation that there are plenty of spiders of some sort in the house. That doesn’t bother me, since I know that most spiders feed on other pest insects, so keeping a few spiders around the house is actually beneficial. In fact, Dunn found that those who are the best housekeepers probably have more pest insects in their house than those who aren’t, since it’s easy to find and eradicate spiders and much harder to find and eradicate all the pests that spiders eat.
When I checked my windowsills and light fixtures, I discovered the remnants of other bugs that called my house their home – flies, daddy longlegs, midges and lots more that I couldn’t identify. The North Carolina researcher said that every house he sampled, including his own, had at least 100 species of spiders, flies, ants, beetles and other bugs living inside. Most go entirely unnoticed.
The surprising truth about the abundance of life living in our homes is that most of it is good for us. Biodiversity, whether in the rainforests or the African plains or inside Rhode Island homes, is a sign of a healthy ecosystem. Scientists say it builds up our resistance to allergens and strengthens our immune system. The thousands of species that live in the average home are working together to keep bad things at bay and good things in manageable numbers.
So don’t worry too much about disinfecting your home to eradicate all non-human life. You’ll never succeed. And nor should you want to. The more diversity in your home the better. Up to a point.
This article first appeared in the Newport Daily News on July 19, 2021.