Pennsylvania is home to a variety of spider species, some harmless and some potentially dangerous. Spiders play an important role in controlling insect populations, but they can also pose risks with their venomous bites. This guide covers the most common spiders found in Pennsylvania, how to identify them, and whether they are a threat.
Overview of Spiders in Pennsylvania
There are over 500 species of spiders that reside in Pennsylvania. While the majority are not harmful to humans there are a few venomous species to watch out for. Some of the most frequently encountered spiders in the state include
- Wolf spiders
- Jumping spiders
- Orb weavers
- Cellar spiders
- Fishing spiders
- Sac spiders
- Crab spiders
- Black widows
Wolf spiders and jumping spiders are abundant hunting spiders that do not spin webs to catch prey. Orb weavers construct intricate web designs used to trap insects. Cellar spiders build messy cobwebs in dark corners of cellars and basements.
Fishing spiders live near water sources and can walk on the water’s surface. Sac spiders hide in silken tubes and are often unwelcome home invaders. Crab spiders lie in ambush within flowers waiting to grab unsuspecting pollinators.
The infamous black widow is one of the few spiders in Pennsylvania whose bite can have severe effects in humans
Wolf Spiders
Wolf spiders are common ground dwellers found throughout the state. There are at least 13 different wolf spider species in Pennsylvania.
Some of the most common include the Carolina wolf spider, rabid wolf spider, hogna wolf spider, and trotter wolf spider. Females range from 0.4 inches to over 1 inch in body length depending on species.
Wolf spiders are robust, hairy spiders that vary in color from grayish-brown to black with stripe or blotch patterns on the abdomen. They have eight eyes arranged in three rows.
Instead of spinning webs, wolf spiders hunt on foot, actively chasing down insect prey. They live on the ground in leaf litter, under rocks or logs, and within low vegetation. Wolf spiders frequently wander into homes by accident.
If disturbed, they may lunge or bite in self-defense but are not aggressive spiders. Their venom only causes mild symptoms in humans like irritation, swelling, or itchiness around the bite site.
Jumping Spiders
There are around 50 species of jumping spiders found in the state. Some of the most common include the daring jumping spider, gray wall jumper, tan jumper, and zebra jumper.
Jumping spiders are compact, hairy spiders that reach 0.1 to 0.5 inches long depending on species. They are usually recognized by their short, stout front legs and ability to leap several times their own body length.
Colors and patterns vary widely, from dull tan or brown to brightly colored with bands, spots, or stripes. Jumping spiders have a square-shaped front profile and large forward-facing eyes that give them excellent vision.
Instead of building webs, jumping spiders actively hunt prey during the day. They stalk close to their target before pouncing. Some species wander indoors but are not considered dangerous to humans. Their small jaws cannot easily penetrate human skin.
Orb Weavers
Orb weaver spiders construct circular webs with spokes radiating from a central hub. There are around 170 orb weaver species found in the state.
Some typical orb weavers in Pennsylvania include the barn spider, garden spider, shamrock spider, marbled spider, and long-jawed orb weaver. Most have rounded abdomens and colorful patterns on their bodies.
Females are larger than males, ranging from 0.2 to 1 inch long. Orb weavers have eight eyes, with the front middle pair being particularly large. They build intricate, sticky webs outdoors between vegetation to catch flying insects.
Bites from orb weavers are rare and cause only mild, localized pain. Many orb weaver species actually help control pest insect populations in gardens.
Cellar Spiders
Cellar spiders, also called daddy longlegs spiders, are delicate spiders with long legs and small bodies. There are two common species: the long-bodied cellar spider and dusky cellar spider.
They build messy, tangled webs in dark corners of basements and cellars, where they catch other spiders or insects. Cellar spiders can reach 2 inches in legspan but only 0.2 inches long.
Their legs are thin, evenly spaced, and angular. The body is brown or gray. Cellar spiders sometimes wander into homes but are harmless to humans. They do not have venom capable of piercing human skin.
Fishing Spiders
Fishing spiders are large, semi-aquatic spiders found near streams, ponds, lakes, and wetlands. Some fishing spiders in Pennsylvania exceed 1 inch in body length.
Common species include the banded fishing spider, raft spider, and dark fishing spider. They have an oval abdomen and legs with dark bands. Coloration ranges from brown to gray.
As their name suggests, fishing spiders prey on insects and small fish near the water’s surface. They can dive underwater to catch food and some even construct underwater cocoons for their eggs.
Fishing spiders may wander indoors by accident. They can inflict a painful bite if handled but are not aggressive toward humans.
Sac Spiders
Sac spiders are venomous spiders that do not spin webs for catching prey. Instead they hide in silken sacs or tubes concealed in corners or crevices. Pennsylvania is home to several sac spider species.
The northern yellow sac spider and the brown recluse spider are two common sac spiders found in the state. They can reach 0.5 inches long with a dark abdomen and light leg coloring. The recluse spider has a distinctive violin shape on its back.
Sac spiders hunt insects at night. They sometimes invade homes and build sacs in wall voids, furniture, or piles of stored items. Bites can occur when sac spiders get trapped against human skin.
Recluse spider bites cause mild symptoms but in rare cases can trigger severe skin lesions. The yellow sac spider’s bite is painful but less harmful.
Crab Spiders
Crab spiders are sit-and-wait predators that lie in ambush within flowers. They have a laterigrade posture where their legs extend out to the sides, resembling crabs. There are over 200 crab spider species in North America.
Some common species in Pennsylvania include the goldenrod crab spider, whitebanded crab spider, and flower crab spider. They can range from 0.1 to 0.6 inches long. Coloration varies from white to yellow with some having brown stripes on their legs or abdomen.
Crab spiders have an enlarged front pair of legs used for grabbing prey. They do not spin webs but instead wait motionlessly for pollinators to arrive at the flowers they inhabit. The venom of crab spiders is not considered medically significant to humans.
Black Widow Spider
The famous black widow is one of the few medically significant spiders found in Pennsylvania. Adult females reach 0.5 inches long and have a shiny black body with a red hourglass marking on the underside of their bulbous abdomen.
Black widows build messy webs outdoors in sheltered spots like woodpiles, debris, outdoor furniture, or structural voids. The webs help the spiders snare insect prey.
Female black widow bites can be serious. Their neurotoxic venom is reported to be 15 times more potent than a rattlesnake’s. Bites cause muscle spasms, abdominal pain, and nausea. But deaths are rare and antivenom exists.
Spider Bite Symptoms
Most spider bites only cause minor effects like pain, itching, or redness at the site. Seek medical care if you experience severe symptoms like:
- Intense pain spreading from the bite site
- Nausea, vomiting, or abdominal cramping
- Muscle spasms or rigidity
- Difficulty breathing
- Feeling lightheaded or dizzy
- Rash, blisters, or skin ulcers developing on the bite
Spider Bite Treatment
For mild spider bites, these self-care measures can help manage symptoms:
- Clean the bite area with soap and water to prevent infection.
- Apply an ice pack wrapped in cloth to reduce swelling and pain.
- Keep the bite elevated if possible.
- Take an over-the-counter pain medication like acetaminophen.
- Avoid scratching or irritating the bite.
Consult a doctor for evaluation of moderate or severe symptoms, especially if signs of infection develop. More serious bites may require hospital treatment, pain medication, antivenom, or antibiotics.
Monitor any bite for worsening redness, swelling, pain, or skin changes, as this can indicate a severe reaction. Seek emergency care if serious symptoms appear.
Preventing Spider Encounters
You can reduce run-ins with spiders around your home using these pest prevention tips:
- Seal cracks and crevices on the home exterior to block entry points.
- Install door sweeps and screen small vents to keep spiders out.
- Remove clutter like piles of debris or firewood stacks near the home.
- Prune back vegetation touching the home.
- Turn off exterior lights at night to avoid attracting insects that spiders prey on.
- Vacuum and dust regularly to remove webs inside.
- Store boxes up off the basement floor and check items before grabbing.
- Be cautious when cleaning rarely used spaces like attics or sheds where webs accumulate.
While most spiders in Pennsylvania are harmless, it’s still wise to take precautions around species capable of inflicting painful bites. Knowing how to identify common spiders can help assess any risks if spiders are found near your home.
Types of Spiders in Pennsylvania, New Jersey and Delaware
Because there are more than 45 different species of spiders in the state, we’ll review just a few of the most common spiders found in Pennsylvania.
Interestingly two of the types of spiders you may be most familiar with —the black widow and brown recluse — are not commonly found in Pennsylvania. They do sometimes make their way into the region through shipping from other places.
(Lycosidae) Wolf spiders are perhaps the most notable type of spider found in Pennsylvania. Wolf spiders are carnivorous spiders that are a useful part of the food chain by killing other insects. Like their namesake, the wolf, wolf spiders are “sprinters” and hunt down their prey. This type of spider ranges from 10-35 millimeters in size, has eight eyes, and is known to have excellent vision. Wolf spiders are nocturnal and hunt at night. The venom of a wolf spider does not cause necrosis, but a bite from this spider can be painful and lead to swelling. An allergic reaction to a wolf spider bite, which is rare, may lead to symptoms like nausea, dizziness and rapid pulse.
(Parasteatoda tepidariorum) Common house spiders, also known as “American house spiders” as its name suggests, are the type of spiders you might find in your home. These nuisance pests measure at about 5-8 millimeters, have eight eyes, an elongated abdomen and are brown to light tan in color with shiny skin and dark brown stripes in a pattern similar to a candy cane. Common house spiders do not hunt for prey. Instead, they maintain webs and travel from one to another seeking trapped food. A bite from a common house spider will leave a red, itchy welt but most likely will not cause other health issues.
(Vespula germanica) American nursery web spiders are sometimes confused with wolf spiders because they look very similar. The difference is that their eyes are arranged in two rows rather than three. This type of spider does weave webs to hold their eggs but also actively hunts for prey. Females are about 12-15 millimeters long while males are between 9-15 millimeters.
(Larinioides sclopetarius) Bridge orb weaver spiders measure differently whether they are male or female. Females are about 10 and 14 millimeters long while males are between 8 and 9 millimeters long. This type of spider builds webs on manmade structures like bridges and prefers to be in the sunlight.
(Trachelas tranquillus) Broad-faced sac spiders are most commonly found in Pennsylvania under stones, boards or crawling on window sills or siding. Female broad-faced sac spiders are about 7-10 millimeters long while males are between 5-6 millimeters. This type of spider eats dead insects and other spiders.
Signs of an Infestation
Keeping an eye out for spider webs in your home is an effective way to check for signs of a spider infestation. Be sure to look in dark areas, along with corners, ceiling beams and chandeliers. You may also notice spider eggs — these are white web balls near an active web. Also look for spider droppings or the actual physical presence of spiders in your home.
Are Joro spiders in Pennsylvania?
FAQ
Are there poisonous spiders in PA?
Spider bites are rare, and medically significant incidents are even less common, according to Penn State Extension, the university’s science-based information agency. Primarily, arachnid-fearing Pennsylvanians need to worry about only one spider species in the rare event of a bite: the black widow.
What is the most common spider in PA?
According to Western Pest Services, the Triangulate House Spider is not only the most common spider in Pennsylvania but all of North America. They are typically found in garages and basements.
How can I identify a spider in my home?
To determine if there is a spider in your room, you can look for the following signs: Webs: Check corners, ceilings, and furniture for spider webs. Different spiders create different types of webs, but their presence often indicates a spider nearby. Droppings: Small, dark spots on surfaces can be spider droppings.