As the weather gets cooler, many homeowners notice spiderwebs inside their basements, attics, bathrooms, or other living spaces. The good news is that most spiders are harmless, and many eat common house insects like roaches, flies, and millipedes that we don’t like having around. But unlike other types of household pests, a few spiders can be downright dangerous. If you’re bitten by a black widow or a brown recluse, it can be a medical emergency.
Whether you find them intriguing or icky, spiders are fascinating creatures. One interesting thing is that spiders are arachnids, not insects. They have eight legs (insects have six), six or eight eyes (not two), and special silk-producing glands called spinnerets on their abdomens. And while you don’t always see them, spiders are numerous. One study counted 5.5 million spiders in a single undisturbed, 2.5-acre grass field in England!
Spiders use venom to paralyze and capture their prey. However, only two types of spiders in the U.S. can be dangerous to humans: black widow spiders, known for the red hourglass marking on the underside of their abdomen, and brown recluse spiders, found in the central Midwest from Ohio to Nebraska, and in the south from Texas to Georgia. If you think you may have been bitten by one of these, you should seek medical attention.
Among the most intriguing aspects of spiders are their webs. Their effectiveness in catching prey has allowed spiders to populate every continent except frigid Antarctica. Webs also double as hiding places, storage for eggs, or simply a living space. Spiderwebs even hold a special place in our culture, from the dusty cobwebs featured in horror flicks to the “terrific” webs in the classic children’s book, “Charlotte’s Web.” You can spot spiderwebs in almost every imaginable place — even underwater.
Not all spiders spin webs, but those that do are crafty little architects. In creating a web, the spider must size up a space, find anchor points, and factor in the quantity of available silk. A spider works with as many as eight different types of silk, each from a separate gland in its body, including sticky and nonsticky varieties.
Webs appear delicate and transparent, but they are strong enough to stop an insect hurtling toward them at a tremendous speed. Ounce for ounce, the tensile strength of spider silk is greater than that of steel, and much more elastic. Scientists have looked to spider silk for clues to manufacture military protection, medical devices, and consumer goods. Spiderwebs were once used in traditional medicine to treat wounds and cuts, as they are rich in vitamin K, which may help reduce bleeding and speed healing.
If you spot spiderwebs in your home or yard, knowing the basic types can help you identify the invaders:
Orb webs: These classic, wheel-shaped webs have been around for as long as 100 million years, spun by spiders that evolved around the same time that flying insects emerged. This web’s durable silk frame connects outer bridge lines with internal anchor lines that form spokes. An elastic capture thread binds the spokes together, enabling the web to capture oncoming insects. With an orb web, a spider can catch as many as 250 insects in a single day. Orb weavers are frequent remodelers, often redoing their webs daily.
Tangled webs: Also known as cobwebs, these webs appear messy and shapeless. They’re usually the work of the harmless common house spider or the notorious black widow. Each web is a jumble of threads, anchored to the corner of a ceiling or some other support. Some tangled-web spiders form groups of as many as a thousand to create webs spanning hundreds of yards that are capable of catching almost anything, from flies to birds to other vertebrates.
Funnel webs: Typically nestled between rocks, in dense plant cover, or other sheltered places, these nonsticky funnel-shaped webs serve as hiding spots where spiders lay in wait to pounce on prey. The hobo spider is the most common funnel web-weaving spider in North America. Funnel webs may also be used to store eggs, and in some cases are places where males cohabit with female spiders until mating time. Spiders that spin funnel webs in the U.S. are harmless, but there is a type of funnel-web spider in Australia that makes many lists of “deadliest spiders.”
Tubular webs: These webs run along the bases of trees or on the ground. Spiders hide in tubular webs until prey triggers a silken line radiating from the web. Tubular-web-spinning spiders are typically part of the family Segestriidae and are found around the world.
Sheet webs: These slightly concave webs are strung across bushes, blades of grass, or tree branches, and act like a deadly hammock for passing bugs. These are the handiwork of the sheet-web weaver, including the hammock spider, native to North America.
Although it’s fun to learn about and observe spiders, they’re still unwanted guests indoors. As with so many common household pests, your best defense is keeping them out of your home in the first place. Here are some tips:
Once spiders get into your home, it can be difficult to eliminate them. Because they often don’t crawl on floors, spiders aren’t as vulnerable to pest control treatments as other common household bugs. If spiders have invaded your home or yard, call HomeTeam for an inspection and treatment at 855-855-4873, or visit https://pestdefense.com.