By Mick Swasko, RedEye
10:29 AM CDT, July 13, 2012
Arachnophobic Chicagoans want to hear "flying" and "spider" in the same sentence probably as much as "ketchup" and "hot dog."
But that's the phrase that the bug-squeamish have been treated to this week, when a note posted to guests at the Hilton Chicago Magnificent Mile Suites was passed around online Wednesday. The note warns guests to keep their suite windows closed during their stay, as "the annual migration of High Rise Flying Spiders" has begun, labeling the arachnid "known specifically as the Larinioides sclopetarius" as a "Chicago Phenomenon."
The note continues that buildings including the Willis Tower, John Hancock and lake-shore high rises are beginning to notice an "influx" of the young spiders, which use their webs as a "balloon" to catch air currents to find a suitable place for a web.
But fear not, the Field Museum's Jim Louderman, a collections assistant for insects, said that besides the spider's preference for heights, some of the hype is overblown.
"It caused a tremendous amount of panic," he said. "It's totally unnecessary."
The spider is found all over the U.S., he said, and is hardly a phenomenon unique to Chicago. Native to cliffs, the spiders gravitate toward higher ground, and in the city, he said, high rises are as close as they can get. The Larinioides sclopetarius is one of several spiders that disperses this way and does particularly well in urban environments, he said.
But Louderman said "flying" isn't quite the right terminology for the juvenile eight-leggers. Their floating is more akin to spiders ballooning into the wind at the end of "Charlotte's Web" than deadly face-pouncing in horror films like, say, "Arachnophobia." The ballooning is done when the spider is about the size of a pinhead. The search for higher ground can make a hotel window look preferable, as bright lights attract other bugs once their orb-shaped web "which resembles a dream catcher" is spun.
Despite the panic, Louderman said the spiders won't bite humans, and even though they are venomous, its potency is between that of a mosquito and a honey bee. Once mature, the spider grows to about the size of a half dollar with legs outstretched, with an abdomen about the size of a dime or nickel. They mate in the late-summer and early fall, to have their eggs hatch the next spring and summer.
"These spiders have been doing this forever; it's not something new this year or a phenomenon this year," he said. "I've been here 16 years and I get (calls about) them every year."
firstname.lastname@example.org | @mickswasko
Copyright © 2014 Chicago Tribune Company, LLC