Many pest control professionals, urban entomologists, and PETA members would argue that most indoor spiders are not pests because they do not damage property or pose a nuisance within homes. However, most homeowners would likely disagree, as spider control services generated more revenue for the pest control industry than bed bug control services between 2000 and 2017. Pest control professionals are happy to perform spider control services on both residential and commercial properties, but common indoor spiders, or “synanthropic” spiders are generally categorized as “aesthetic pests,” rather than structural pests. In other words, spiders are pests when they enter homes because they look scary, and not because they pose a danger, damage property, or annoy residents.
Some synanthropic spider species can become indoor nuisance pests in certain circumstances. For example, a large number of cobwebs can become an indoor annoyance, and spiders often enter homes in large numbers to prey on insects already present in the structure. While not a serious issue in the northeast, an indoor presence of either a black widow or recluse spider species should always be addressed by a pest control professional as soon as possible due to the health threat these spiders pose to humans and pets. The 13 recluse spider species known to inhabit the US cannot be found in the northeast, but due to the synanthropic habits of brown and Chilean recluse species, these two spiders often find their way into luggage, moving boxes, plant materials, and other items that take them outside of their habitat range.
Surprisingly, an extensive infestation of Chilean recluse spiders existed for many years in the collections basement of the Museum of Comparative Zoology at Harvard University. This infestation started when the spiders hitchhiked from their native South America to Massachusetts within museum collection cargo. Of the five widow spider species in the US, the northern black widow is the only one that can be found in Massachusetts. The northern black widow has been known to inflict bites on humans on residential properties in Massachusetts, but such incidents are very rare. Maintaining an insect-free dwelling will prevent spiders from entering homes to seek insect prey, and sealing entry points that spiders can exploit to access indoor areas should be sealed.