Editor’s Note: The following article appeared in Mike Merchant’s blog, “Insects in the City,” which can be found at insectsinthecity.blogspot.com. The blog offers readers news and commentary about the urban pest management industry and is excerpted here with permission of the author.

Last year an article was published by Matthew Bertone and colleagues at North Carolina State University about arthropods found in homes. The only organism found in 100 percent of the homes and more than 90 percent of the basements surveyed was spiders. The only other organisms that came close were flies and ants and carpet beetles. By contrast, German cockroaches were found in only 6 percent of homes and fleas in 10 percent of homes.