The more upscale your neighborhood, the more bugs live with you, a study says.

Scientists found that homes in wealthier areas house at least 100 different kinds of flies, spiders, beetles and ants. However, the study published Tuesday in the journal Biology Letters found that most bugs were not pests, although dust mites and book lice were fairly common. Wealthier neighborhoods are more biologically diverse as a result of the different kinds of plants in gardens and hence home to a variety of birds, bats and lizards, in addition to anthropods. Scientists called this the “luxury effect.”

“Our unexpected, and perhaps counterintuitive finding highlights how much we have yet to learn about indoor ecology,” the study’s lead author Misha Leong from the California Academy of Science reportedly said.

Scientists sampled 50 homes in Raleigh, North Carolina selected at random. “We didn’t go through drawers or closets looking for secrets,” Leong reportedly said, “But we did spend a lot of time on our hands and knees sweeping up samples.” They didn’t count the number of anthropods found in each home, just the number of species. The researchers found that the average home had nearly 61 distinct anthropod families.

The study discovered that wealthier homes had nearly 100 different kinds of bugs on an average while poorer homes had just 50. Researchers found that the age of the house wasn’t a factor in the different species of bugs present in it but the number was linked to the size of the house, the average local income and the variety of plants found in the area.

“As more of the planet becomes urbanized, the proportion of the ecological world potentially influenced by human socioeconomics will increase,” the scientists told the Guardian. “Our work suggests that the management of neighborhoods and cities can have effects on biodiversity that can extend from trees and birds all the way to the arthropod life in bedrooms and basements.”