Nursery web spiders are relatively large-sized spiders that closely resemble wolf spiders and yellow sac spiders in appearance. The intimidating size of these spiders can be frightening to homeowners who encounter specimens indoors. It is not uncommon for pest control professionals to be called to homes where a resident became frightened after spotting one single specimen indoors. Nursery web spiders can be found throughout the northeastern states, especially within and around residential homes. The most commonly encountered nursery web spider species in the northeast, Pisaurina mira, naturally inhabits gardens and shrubs where they construct a silk web “nursery” for their offspring. Adults strategically build these nurseries behind leaves and other forms of plant matter where they remain well-hidden from predators. Nursery web spiders may be the most commonly encountered spiders in the eastern half of the US, and although these spiders are somewhat large in size, they are considered harmless to humans.
The Pisaurina mira species of nursery web spider sees females grow between half an inch and an inch in body length, while males are somewhat smaller. According to an informal survey, this species is spotted more often than other common garden spider species in the east, and one third of all documented sightings occurred indoors, while the majority occurred within yards and on structures. This species can be recognized for its bulbous abdomen and tan to dark brown colored exterior. The Pisaurina mira species can also be distinguished by their eight eyes that form one straight row of four eyes in front another U-shaped row of eyes. People living in homes that are located near wooded habitats are likely to see an occasional nursery web spider indoors, and while these spiders are large enough to inflict a painful bite, their venom is not considered medically significant. Nursery web spiders are also known for preying upon aquatic specimens, like tadpoles. When foraging, these spiders can dive below the water’s surface and they are sometimes spotted traversing the water’s surface in pursuit of prey.
Have you ever spotted a nursery web spider within your home?