Spiders of Pennsylvania: 10 Species

Pennsylvania is home to a diverse array of spider species, each with its own unique characteristics and ecological role. These eight-legged creatures, often misunderstood and feared, play a vital part in the state’s ecosystems. From master weavers to skilled hunters, spiders contribute to natural pest control and serve as indicators of environmental health. Let’s delve into the world of these arachnids and explore the top 10 spider species found in Pennsylvania.

The Black and Yellow Garden Spider

Argiope aurantia, commonly known as the Black and Yellow Garden Spider, is a striking species found across Pennsylvania. These spiders are easily recognizable due to their vibrant yellow and black patterns, often with a distinct hourglass shape on their abdomen. They are master architects, constructing large, intricate webs that can span several feet. These webs, typically built in gardens and open areas, are a true display of engineering prowess.

The Black and Yellow Garden Spider is diurnal, meaning it hunts during the day. Its web serves as both a home and a trap, capturing various flying insects. This species is non-aggressive and will often flee when disturbed, making it a welcome guest in many gardens.

Northern Black Widow

The Latrodectus variolus, or Northern Black Widow, is a species that demands respect and caution. Native to Pennsylvania, this spider is easily identified by its shiny black body and the iconic red hourglass shape on its abdomen. Despite its small size, the Northern Black Widow is highly venomous and should be approached with care.

Female Black Widows are typically more dangerous than males, as they possess larger venom glands. However, these spiders are generally reclusive and prefer to hide in dark, sheltered areas like woodpiles or outbuildings. They rarely bite humans unless provoked, and their venom, while potent, is rarely life-threatening to adults.

Bold Jumping Spider

Phidippus audax, the Bold Jumping Spider, is a charismatic species that captivates with its bold behavior and striking appearance. These spiders are characterized by their quick movements and excellent eyesight, which they use to hunt down prey with precision. Despite their name, they rarely jump onto humans and are generally harmless.

The Bold Jumping Spider is known for its curiosity and intelligence. It can navigate complex environments and even use tools, making it one of the most fascinating spider species in Pennsylvania. With their vibrant colors and active nature, they are a delight to observe for arachnophiles.

Spinybacked Orbweaver

Micrathena species, commonly referred to as Spinybacked Orbweavers, are a group of spiders known for their unique appearance. These spiders have a distinct, spiky abdomen, which gives them a fearsome look despite their small size. They are typically brightly colored, with combinations of yellow, orange, and red.

Spinybacked Orbweavers are skilled weavers, creating beautiful, wheel-like webs that they use to capture flying insects. Despite their intimidating appearance, they are completely harmless to humans and are an essential part of the ecosystem, helping to control insect populations.

Carolina Wolf Spider

Hogna carolinensis, the Carolina Wolf Spider, is one of the largest wolf spiders in North America and can be found in various habitats across Pennsylvania. These spiders are formidable predators, known for their speed and agility. They are active hunters, often pursuing their prey on the ground rather than relying on webs.

The Carolina Wolf Spider is a nocturnal species, spending its days hidden in burrows or under rocks. Despite their intimidating size, they are generally shy and will avoid human contact. Their role in controlling insect populations, especially harmful pests, makes them a valuable part of the ecosystem.

Marbled Orbweaver

Araneus marmoreus, or the Marbled Orbweaver, is a species that adds a touch of elegance to Pennsylvania’s arachnid community. These spiders are known for their intricate, marbled patterns in shades of brown and cream. They construct large, circular webs that are often adorned with stabilimenta, which are decorative silk structures that may serve to attract prey or deter predators.

Marbled Orbweavers are typically docile and will retreat when disturbed. They are an important component of the food chain, serving as prey for various birds and other predators while also contributing to natural pest control.

Six-spotted Fishing Spider

Dolomedes triton, the Six-spotted Fishing Spider, is a unique species that has adapted to a semi-aquatic lifestyle. These spiders are often found near bodies of water, where they hunt for prey such as insects, small fish, and even tadpoles. They are skilled swimmers and can dive underwater to catch their prey or to escape potential threats.

The Six-spotted Fishing Spider is named for the six distinct spots on its abdomen, which serve as a form of camouflage when the spider is perched on leaves or twigs near the water’s surface. They are an essential part of aquatic ecosystems, helping to maintain the balance of species in and around Pennsylvania’s waterways.

Yellow Sac Spider

Cheiracanthium species, collectively known as Yellow Sac Spiders, are common household spiders in Pennsylvania. These spiders are often encountered indoors, where they build small, silken sacs in corners or behind furniture. They are active hunters, typically foraging at night, and are known to prey on other spiders and insects.

While Yellow Sac Spiders are not aggressive towards humans, their bites can be painful and may cause localized swelling and discomfort. However, their venom is not considered dangerous, and serious health complications are rare.

Bold Jumping Spider

Phidippus audax, the Bold Jumping Spider, is a species that captivates with its unique characteristics and behavior. As mentioned earlier, these spiders are known for their bold demeanor and exceptional hunting skills. Their excellent eyesight and agile movements make them efficient predators, often targeting other spiders and insects.

The Bold Jumping Spider is a true ambassador for arachnids, helping to dispel fears and misconceptions about spiders. Their curious nature and willingness to interact with humans make them a favorite among spider enthusiasts.

Barn Funnel Weaver

Tegenaria domestica, commonly known as the Barn Funnel Weaver, is a species that has adapted to living in close proximity to humans. These spiders are often found in barns, sheds, and other outbuildings, as well as in basements and attics. They are named for the funnel-shaped webs they construct, which serve as both a living space and a trap for unsuspecting prey.

Barn Funnel Weavers are generally harmless to humans and are considered beneficial due to their role in pest control. They are efficient predators, capturing and consuming a variety of insects that may be considered nuisances or pests.

Conclusion:

Pennsylvania’s arachnid diversity is a testament to the state’s ecological richness. From the vibrant webs of the Black and Yellow Garden Spider to the aquatic adaptations of the Six-spotted Fishing Spider, each species contributes uniquely to the ecosystem. While spiders often evoke fear and misunderstanding, a closer look reveals their crucial ecological roles and fascinating behaviors.

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