In the lush woodlands, sprawling fields, and suburban neighborhoods of Pennsylvania, spiders are an integral part of the ecosystem, playing a crucial role in pest control and biodiversity. With over 900 spider species documented in the state, identifying the most common ones can be both fascinating and practical for residents. This article delves into the common spiders in Pennsylvania, their behaviors, habitats, and the roles they play in local environments.
1. The Black Widow Spider (Latrodectus variolus)
The Northern Black Widow is a rare but significant presence in Pennsylvania, primarily found in wooded areas, sheds, and outbuildings. Females are easily identified by their glossy black bodies and distinctive red hourglass marking on the underside of their abdomen. While their bite is venomous and can cause severe pain, it is rarely life-threatening to humans. These spiders are reclusive and prefer undisturbed spaces.
2. The Bold Jumping Spider (Phidippus audax)
The Bold Jumping Spider is a frequent sight in gardens, fields, and even on exterior walls of homes. Known for their excellent vision and agile jumps, these spiders are harmless to humans and are often observed stalking prey with precision. Their compact bodies, typically black with white or orange markings, make them easy to spot. Jumping spiders are diurnal and curious, sometimes even tilting their heads to observe humans.
3. The Common House Spider (Parasteatoda tepidariorum)
Cons: Webs can be a nuisance in homes.
The Common House Spider is a ubiquitous sight in Pennsylvania homes, garages, and sheds. These spiders are small, with a bulbous abdomen and varying shades of brown or gray. They build messy, irregular webs in corners and crevices, where they capture small insects like mosquitoes and flies. While their webs may be unsightly, these spiders are beneficial and pose no threat to humans.
4. The Wolf Spider (Lycosidae family)
- Wolf spiders are ground-dwelling hunters, often found in grassy areas or under rocks.
- They do not spin webs to catch prey but chase it down with remarkable speed.
- Females carry their egg sacs and young on their backs, a unique trait among spiders.
Wolf spiders are among the largest spiders in Pennsylvania, with some species growing up to 1 inch in body length. Their robust bodies and hairy legs give them a formidable appearance, but they are generally shy and avoid human contact. While their bite can cause localized pain, it is not medically significant. These spiders are essential predators, keeping populations of insects in check.
5. The Orb-Weaver Spider (Araneidae family)
Pennsylvania is home to numerous species of orb-weaver spiders, including the striking Black and Yellow Garden Spider (Argiope aurantia). These spiders are often found in gardens, fields, and forests, where they construct large, symmetrical webs to catch flying insects. Orb-weavers are generally harmless to humans and play a vital role in controlling pest populations. Their colorful bodies and elaborate webs make them a favorite among nature enthusiasts.
6. The Cellar Spider (Pholcidae family)
Cons: Their long, thin legs and irregular webs can be unsettling.
Often called “daddy long-legs,” cellar spiders are common in damp, dark areas like basements, cellars, and crawl spaces. Their elongated legs and small bodies give them a distinctive appearance. These spiders are known for their ability to prey on other spiders, including more dangerous species like the black widow. Despite their eerie look, cellar spiders are harmless to humans and are considered beneficial.
7. The Fishing Spider (Dolomedes species)
Found near ponds, streams, and wetlands, fishing spiders are unique among Pennsylvania’s arachnids. These large, brown spiders have the ability to run across water surfaces to catch prey like small fish and insects. While their size and appearance can be intimidating, they are not aggressive toward humans. Fishing spiders are an essential part of aquatic ecosystems, contributing to insect control.
Identifying and Coexisting with Pennsylvania’s Spiders
To identify spiders safely, use a magnifying glass or camera to observe their characteristics without handling them. If you encounter a spider indoors, consider relocating it outdoors rather than killing it. Regularly cleaning webs and sealing entry points can help manage spider populations in homes.
Are there dangerous spiders in Pennsylvania?
+While the Northern Black Widow is venomous, encounters are rare. Most spiders in Pennsylvania are harmless and beneficial.
How can I prevent spiders from entering my home?
+Seal cracks, keep windows screened, and reduce clutter. Regularly clean areas where spiders build webs.
Do spiders in Pennsylvania bite humans?
+Spiders generally bite only when threatened. Most bites are minor and require no medical attention.
What should I do if I find a spider in my home?
+Use a container to gently relocate the spider outdoors. Avoid squashing it, as this can attract other pests.
Conclusion
Pennsylvania’s spiders are a diverse and fascinating group, each playing a unique role in the state’s ecosystems. From the industrious orb-weavers to the reclusive black widows, these arachnids are more than just creepy-crawlies—they are essential contributors to biodiversity. By understanding and appreciating their behaviors, residents can coexist with these remarkable creatures while maintaining a healthy balance in their surroundings.
