This story appears in the July 2018 issue of National Geographic magazine.
Freeloaders come in all sizes. A study of 50 houses in the Raleigh, North Carolina, area, reported in the journal Peer J, found hundreds of species of arthropods living with unwitting homeowners. Most (73 percent) were flies, spiders, wasps, ants, and beetles, like the varied carpet beetle above. Also found: moths, earwigs, cockroaches, and millipedes.