Chicago ? Midwestern spiders always get big as they prepare to lay eggs, but this year they’re even fatter thanks to a cool, wet summer that sustained their favorite snack: insects.

“Right now they’re eating like kings,” said Field Museum entomologist Petra Sierwald. “They’re having a very good time.”

People throughout the Midwest are noticing the corpulent arachnids everywhere from bushes to the windows of high-rise buildings.

Randall Deutsch said lately he’d noticed armies of spiders clinging to the outside of office windows where he works as an architect.

“It’s one of the strangest things to see spiders on upper floors,” said Deutsch, 43, of Winnetka. “Maybe they’re trying to escape the city and heat like everyone else.”

Former high-rise window washer Russell Hendericks said he’d seen workers drop their tools when spiders crawled on their hands.

“Spiders don’t bother me, but my partner is petrified,” said Hendericks, who took over as owner of H & M Window Cleaning and Building Maintenance in Chicago this month. “He goes home and takes a bath and has them in his hair.”

Donald Webb, an entomologist with the Illinois Natural History Survey, said spiders were often plentiful and plump this time of year.

“There’s usually more spiders this time of year because there are more insects out,” Webb said. “There’s just more food out there for them.”

Garden spiders such as this one are argiopes, which are common to the Midwest and spin large, orb-like webs that can be found in bushes. The female spiders can grow as long as 2 inches as they prepare to lay eggs, but this year they're even fatter because the cool summer allowed for plenty of insects, the spiders' main food source.

But just how many are there, and how fat are they? Entomologists say it’s hard to pinpoint exact numbers.

The rule of thumb is that no one anywhere is ever more than three feet away from a spider, Sierwald said. There are also 899 known spider species in Michigan, Ohio, Illinois, Wisconsin and Indiana. People just don’t notice the creepy crawlers as much until they fatten up near the end of summer.

Each fall, female spiders can double in size as they prepare to lay eggs. Some spiders, such as female argiopes, which are common to Illinois, can grow as long as 2 inches. Argiopes spin large, orblike webs and can be found in bushes, prairies and well-kept yards.

Other spiders, such as jumping spiders, range in size from tiny to half an inch long and often sneak into people’s houses.

Most spiders in the Midwest will lay their eggs from now through October and then hibernate or die, Sierwald said.

For spider haters, the bad news is that before they die, spiders will lay anywhere from 50 to 1,000 eggs a piece.