The Barn Spider Facts: Behavior, Habitat and More
Contrary to their name, barn spiders can be found anywhere from house porches to rocky caves. These spiders are part of the orb-weaver family of spiders that construct intricate, wheel-shaped webs that they use to catch their prey.
Barn Spider Characteristics
Barn spiders vary in size, depending on the sex of the spider. Measuring from the front of the forelegs to the back of the hindlegs, males typically measure ¾-inch long, while the females are bigger at approximately ⅞-inch long. The bodies of barn spiders can be different shades of light brown to dark brown and their abdomen often has a reddish-brown coloring. The abdomen takes on a circular or oval shape and is covered with tiny red and brown hairs that give the spider a furry appearance.
These pests have long legs that appear thick at the base of the body and grow very thin and pointy at the tips. Their legs are uniquely patterned with striped bands that alternate between varying shades of red, brown, and white.
Barn Spider Behavior
Like other common house spiders, barn spiders primarily eat flying insects like mosquitoes, flies, beetles, and moths. They do this by capturing these insects in their sticky, symmetrical orb webs that often measure between two and three feet wide, though some webs can be as large as 10 feet in diameter. Barn spiders are hard workers; they construct new webs at dusk to catch their prey, only to consume the web in the morning and start anew the next night. During the day, these pests typically hide among leaves and in small crevices to escape their predators, which are primarily birds and larger arachnids.
These webs typically appear spread across multiple surfaces, like two tree branches or within the top corners of a home’s windows and doors. Though these pests are known for having poor eyesight, they rely on sensing vibrations to know if prey is near. If a barn spider does sense the presence of potential prey, they will sway their web in response to stimuli or to assess what was caught.
Barn Spider Habitat
Barn spiders are most commonly found within the northeastern United States and the provinces of Canada, though they have been found as far west as Texas. These pests prefer warmer weather and are more likely to be spotted in the late summer and early fall, from early August through October.
These pests most often inhabit areas with wooden beams and rafters, like barns, porches, sheds, and even boat houses. One interesting barn spider fact is that these pests have been known to eat animals and insects larger than themselves. Fortunately, because of this hefty appetite, it’s unlikely for a barn spider to live inside your house where few insects are present.
Life Cycle and Reproduction Habits
Male and female spiders mate in the fall and the female lays her eggs soon after. When a female barn spider lays eggs, she crafts a small egg sac out of her silk. This egg sac resembles a small butterfly cocoon and can hold hundreds of tiny spider eggs at a time. The female usually dies once the first bout of cold weather hits. Sometimes, the female eats the male after mating.
These eggs then hatch in the early spring and the immature barn spiders are on their own to begin building new webs. Like many other spiders, these spiderlings use a technique called ‘ballooning’ to travel to new locations. They do so by first testing out the wind direction and speed using the small hairs on their legs. Then, they release several strands of silk from their body that catch the wind and lift them into the air. Some barn spiders use this technique to travel just a few feet, while others can be carried multiple miles away. No matter where they travel to, these pests remain active in the summer and fall, until they themselves mate, lay eggs, and die. Because of this, most barn spiders only live between one and two years.
Are Barn Spiders Venomous?
One common misconception about spiders is that many are poisonous, but in fact most spiders are actually venomous. The difference being that poisonous denotes danger when ingested, while venomous denotes danger when bitten. Barn spiders are more likely to hide from a human threat than lash out and bite, though a barn spider bite can still cause slight irritation. However, if you receive a bite from a spider and see more severe symptoms like abdominal cramping, chills, and nausea, the Mayo Clinic Recommends you “call your primary care doctor or go to an urgent care center.”
Barn spiders are typically harmless to homeowners as these pests rarely bite and stay away from indoor spaces. Still, a barn spider infestation can be less than ideal. If you see signs of spider infestations around your property, contact Terminix for more information on our comprehensive, year-round treatment plans for spider infestations.