Y: Hey Don, what are you doing with that jar?
D: Collecting arthropods, Yaël.
Y: You mean crabs?
D: Crabs are a type of arthropod, but an arthropod is an animal with an exoskeleton, segmented bodies and jointed limbs. That includes insects, spiders, mites, and centipedes, too.
Y: You're collecting bugs then?
D: I'm doing some research. Did you know that entomologists from North Carolina State University ran a study that found we share our houses with more than five hundred kinds of arthropods?
Y: Five hundred! That's crazy.
D: I will admit, it's surprising. The researchers took samples from fifty houses during the summer months near Raleigh. They collected both living and dead arthropods from each room. In total, they identified over five hundred different morpho-species. Those are species so closely related that they have to be identified by scientists looking for specific physical traits. Each house had on average about one hundred morpho-species.
Y: There is no way that I have one hundred species of anything living in my house.
D: They mostly collected flies, spiders, beetles, ants, and book lice. Most of the species they found don't normally live in houses. They're arthropods that accidently wandered in from outdoors. For example, they found gall midges in all fifty homes. Midges are small flies that feed on outdoor plants, and can't survive indoors. Believe it or not, only five rooms out of five hundred fifty had no arthropods.
Y: My house is cleaner than that.
D: I bet you have cobwebs.
Y: Well, sure.
D: Those are made by cobweb spiders which were found in sixty-five percent of all rooms sampled. We think our homes are sterile environments, but they're not. I think that might be a good thing.