Cool Critters: Boo! There’s a pumpkin in that big web

The marbled orbweaver, also known as the pumpkin orbweaver, is no creepy crawler. Never mind that it spins a web large enough to stretch across your face should you accidentally walk into one.

This spider works hard, is not aggressive and helps your garden by eating insect pests. It’s also a beauty, resembling a pumpkin with eight legs that spins lustrous silk.

The pumpkin orbweaver is nicknamed for its large, bulbous abdomen that’s often orange. Coincidently, it’s most visible in the weeks leading up to Halloween.

People tend to see more of them this time of year, but not because they’re more numerous, said spider expert Rod Crawford of the University of Washington’s Burke Museum.

“People often refer to autumn as ‘spider season’ because they think there are more spiders. But that’s a myth,” Crawford explained. “After spending all summer feeding and growing, they’ve reached their largest size. They’re conspicuous.”

Scientifically called Araneus marmoreus, the pumpkin orbweaver is found throughout much of the United States and Canada, including here in Washington state.

And it’s the females that are most conspicuous these days. Not only are they almost twice the size as the males, they also build webs as large as 2 feet in diameter.

And oh, what a web she builds. Similar to those artificial webs used as Halloween décor, their wheel-like marvels are often suspended in gaps between trees and shrubs. In suburban areas, you might find see them among tall vegetation in gardens and neighborhood parks or along fence posts and mail boxes – upright objects sturdy enough to anchor the strands of silk that radiate toward the web’s hub.

Within this sticky, dynamic structure, the female sits and waits until a flying insect comes along and gets trapped. Next, she injects the prey with venom and wraps it in silk until she’s ready to eat.

Clearly, pumpkin spiders are dangerous to insects. But not to you, said Crawford, who has spent the past 50 years trying to debunk misconceptions about spiders.

Orbweavers are not harmful to humans, nor are they interested in the warmth of your home because they need vegetation, water and rocks to survive, he said. “They are simply not house spiders.”

The pumpkin orbweaver is one of a huge family of spiders belonging to the family Araneidae, according to the Entomological Society of America. There are roughly 3,500 species worldwide and 180 in North America, the organization says. The species vary in color, but usually display big, rounded abdomens like the pumpkin orbweaver. The many Araneidae cousins are joined by a colorful assortment of common names, including shamrock, banana, arboreal and even the cat-faced orbweaver.

Whether they live in the Inland Northwest, India or Ireland, orbweavers are voracious eaters that control insect populations, said Crawford. Even if you don’t like spiders, you need them in your backyard, in your garden, in the farmer’s field, he added.

So, you might think twice before destroying the large, geometric web located next to the porch light or along a garden path.

“A world without spiders would be far scarier than a world with them,” Crawford said.