Wandering spiders often end up trapped indoors

OK, here's the good news: Arachnids that you'll find in your home this time of year are in search of a few things — and none of them are you.

Warmth, moisture and, er, spider companionship are at the top of their lists.

In the fall, there's "a surge in the number of particularly male spiders coming into the home desperately looking for females," said Paula Cushing, curator of invertebrate zoology at the Denver Museum of Nature and Science. "When the males mature, even web-building males, they stop building webs and they have just one thing on their minds."

They're looking for a mate.

"Males locate females by increased wandering. They're a lot more active so they're moving around more, and with that increased activity they can sometimes make their way into our homes," she said.

Many of them are no happier about being stuck in your house than you are about them being stuck there.

"These are spiders who wander into the house, often making the wrong turn, and can't get out," said Whitney Cranshaw, a professor of entomology and extension specialist at Colorado State University in Fort Collins.

About 10 percent of the world's roughly 35,000 known species of spiders live in North America, but only three native U.S. species are poisonous to humans — the black widow, the brown recluse and the hobo spider. None of those call Minnesota home, said University of Minnesota Extension entomologist Jeff Hahn.

"Sometimes we'll hear about a black widow hitchhiking here in grapes from California," he said, "but I'm not aware of anyone being bitten by one. For all intents and purposes, there are no poisonous spiders in Minnesota."

We have plenty of other spiders, though. A fact sheet (http://tinyurl.com/lwxlfzp) maintained by Hahn designates spiders as either hunting spiders (including wolf spiders, sac spiders and jumping spiders) or web-building spiders (among them, cobweb spiders, orb weaver spiders and funnel weaver spiders).

None of these spiders are harmful.

"They're not aggressive," he said. "Sure, you can get bit by one if it gets trapped under your clothes, for instance. But it's just defending itself, and it's not dangerous.

To cut back on the number of spiders in your home, close any obvious gaps along floorboards and at windows and doors.

Cushing cautions against pesticides. Although she advocates for carefully returning the spiders to the wild, she suggests placing sticky traps, available at hardware stores, on the floor near exterior doors, in basements, in the kitchen and bathroom and around radiators — anywhere there might be dripping or pools of precious water.

Reducing clutter can help, too.

"They seek out hiding places to build nests and retreats, so if you have a lot of clutter on the floor, that's a stable habitat," she said.

Keeping things clean outside helps, too. Hahn recommends keeping piles of bricks, firewood and other debris that might serve as suitable homes for spiders away from the house. While you're at it, cut back shrubs and other plants that directly contact the building.

They might creep us out, he said, but they're our friends.

Staff writer Jeff Strickler contributed to this report.