Countless arthropod species have been documented worldwide, and these species account for the majority of all extant animal species. At more than one million documented species, insects are the most species-rich class of arthropods, followed by arachnids with around 70,000 documented species. Of all animal species known to science, only around one million occur in urban settings where they have a negative impact on humankind, and only around 1,000 insect species fit this description. The indoor arthropod pests that should be addressed by a pest control professional as quickly as possible are those that pose a medical threat, and to a lesser extent, those that inflict economically costly property damage, especially arthropod pests of stored food, and arthropod pests that infest structural wood like termites, carpenter ants, and wood-boring beetles.

Very few arthropod species are considered medically significant, and the only potentially dangerous arthropod pests within homes and buildings in Massachusetts include northern black widow spiders, European fire ants, most cockroach pests, disease-carrying mosquito species, particularly the northern house mosquito, bed bugs, several flea species, filth flies, mites, yellow-sac spiders, aerial-nesting wasp and bee species, and although they can only survive outdoors, ticks. This list does not include medically significant arthropod pests that commonly occur in residential yards, such as ground-nesting wasps, biting flies, blister beetles, biting true bugs, stinging caterpillars, and solitary bees and wasps. Most arthropod species that are classified as indoor pests are nothing more than a nuisance within structures, and therefore, their indoor presence does not warrant urgent professional pest control efforts. The most common arthropod species that pose a nuisance within homes and buildings in Massachusetts include most ant pests, silverfish, brown marmorated stink bugs, web-building house spiders, ground beetles, and many more.

Some indoor arthropod pests that are frequently controlled by pest management professionals are medically harmless, non-destructive, hard to notice, and generally benign in every way, except their appearance may be quite disturbing to certain people, particularly those who fear insects, arachnids and/or other creepy-crawlies. While this fear may be largely unfounded in the majority of cases, many pest control service requests are made by homeowners after they find a single large spider or cockroach indoors. Interestingly, most homeowners do not respond with fear to the indoor presence of medically significant arthropod pests like European fire ants, but spotting a harmless, yet large and hairy Parson’s spider indoors would prompt a large proportion of Massachusetts residents to go running for the hills. The Massachusetts spiders that commonly frighten residents within homes include wolf spiders, grass spiders, fishing spiders, and crab spiders. The few medically significant spider species found in Massachusetts include the northern black widow, but they are very rarely spotted in homes in the state. However, the yellow-sac spider is commonly encountered in Massachusetts homes where they frequently inflict bites to humans, which may, in extremely rare cases, result in tissue necrosis.

Have you ever encountered a visibly hairy spider in your home?