You’re never really home alone.

Even when you think you're enjoying a few moments of blissful solitude, entomologist Misha Leong likes to remind people, you have more tiny roommates than you think.

“Ecologists spend most of their time studying these far-off, exotic places, but we rarely think about the wildlife inside our homes,” says Leong, a postdoctoral fellow at the California Academy of Sciences. “We’re actually surrounded by wildlife, especially bugs, when we’re indoors.” (Related: "500 Kinds of Bugs May Be Living in Your House")

Now a new study shows that wealthier homes have more types of arthropods—which include insects and spiders—than less expensive homes.

Though Americans love the great outdoors, we're spending more and more time in the great