Numerous arthropods are known for being pests within homes in the United Stats, but some arthropods that are not categorized as “pests” may still become a nuisance indoors under some circumstances. For example, many of the most frequently spotted spider species within homes are not considered to be pests by most experts. This is because spiders do not necessarily exploit indoor conditions, and they typically do not remain within human dwellings for long. Pest control professionals often use terms like “occasional invaders” and “incidental invaders” when discussing indoor arthropod pest issues. In the above example, spiders would be considered incidental invaders since most spider species do not deliberately congregate within homes to take advantage of easily accessible resources, like food and shelter; instead, it is more common for one or a few spiders to enter a home inadvertently while hunting or pursuing prey. This is especially true when it comes to wolf spiders, as these spiders are found indoors frequently since they constantly travel around homes in search of live insect prey. Cobweb spiders, cellar spiders and house spiders are a few examples of spiders that do invade homes in order to exploit human habitats.

To put it simply, occasional invaders are arthropod pests that live primarily outdoors but are often found indoors. Generally, in order for an arthropod pest to be considered an occasional invader, it must regularly dwell within the perimeter of residential yards. Some common occasional invaders in the northeast include house centipedes, millipedes, American cockroaches, crickets, earwigs and overwintering pests, such as Asian lady beetles, brown marmorated stink bugs and western conifer seed beetles. Incidental arthropod pests do not maintain a habitat on residential properties, but they may be attracted to homes by outside lights. These insects include mayflies, stoneflies, fishflies, and caddisflies. Incidental arthropod invaders can also be attracted to abundant vegetation on a property. In the northeast, common arthropod garden pests that sometimes wander indoors include wheel bugs, thrips, psyllids, and flying aphids. For the most part, the only reason residents often find spiders in their home is because spiders are attracted to the insect food sources that are prevalent in gardens and on overgrown lawns.

Do you know of any spider species that you think qualifies as an occasional invader?