Several spider species frequently enter homes and buildings, but many of these species cannot accurately be called “house spiders.” Some of the most commonly managed indoor spiders include species that prefer to dwell outdoors, such as wolf spiders, fishing spiders, crab spiders, and woodlouse hunter spiders. These outdoor dwelling spiders often become a nuisance on residential properties where their insect prey are abundant. For example, in order to secure an easy meal, spiders of all sizes tend to congregate near porch lights and other artificial white lights that attract tasty insects like moths and beetles.

Large hunting spiders often chase their insect prey indoors, and despite their preference for outdoor living, hunting spiders are likely to become abundant indoors if large numbers of their insect prey are also present in the structure. Eliminating these spider infestations first requires pest control professionals to eliminate the insects the hungry spiders are seeking within infested homes. In many spider infestation cases, the application of a residual pesticide barrier along doorways and window frames is also a necessity. The most frequently encountered spider species within homes are “synanthropic” spiders, or “house spiders,” as they are more commonly known.

A synanthropic organism is an organism that has adapted to live within and near manmade dwellings where they benefit from human activity, and many urban entomologists refer to synanthropic spider species as “house spiders.” As a result of having adapted to indoor environments, house spiders have lost their ability to thrive outdoors, and most cannot survive for long outside of protected structures. The most common synanthropic spider species found within Massachusetts homes include cellar spiders in the family Pholcidae, the common house spider or “American house spider” (Parasteatoda tepidariorum), the barn spider (Araneus cavaticus), and the barn funnel weaver (Tegenaria domestica).

The medically significant brown recluse and black widow spider species are also synanthropic, and while the northern black widow (Latrodectus variolus) inhabits New England, they are very rarely encountered by humans. While Massachusetts house spiders are considered harmless to humans, the synanthropic yellow-sac spider (Cheiracanthium inclusum) may be an exception. This species is likely responsible for inflicting most of the spider bites reported annually in the US, and their bites cause minor medical issues in rare cases.

Have you ever struggled to control a spider infestation within your home?