Vetter worked with Saupe on her master's project, in which she tracked the spiders' predicted migration through "ecological niche modeling."
She used two models to predict the spider's range in 2020, 2050 and 2080, given the effects of global warming, concluding they might move north but those left behind would die off.
Kansas is a "hotbed" for these spiders, said Saupe, who has predicted that they might become extinct in the southern portions of their range by 2080 as the climate in their natural habitats becomes to warm and their mobility is restricted.
Most are reclusive, as their name suggests, and go nowhere near humans. Those that are threatened can bite, but often with just a "dry bite" that does not emit venom, Saupe said.
It is dormant part of the year, which means bites usually occur from April until October. They tend to come out at night and hide under bedding and clothes, in dark places.
Still, the spiders can be lethal.
ABCNews.com reported in 2010 on Victoria Franklin of Marietta, Ga., who had surgery to remove a necrotic breast after a brown recluse bite.
Franklin, 51, still has kidney and other medical problems related to the bite.
"I have no medical insurance at all," she told ABCNews.com in an email. "Medication is also expensive. I have nine different medications that I have to take every day, sometime twice a day."
Saupe's study co-author, Paul Selden, said the species was "the commonest spider in my house" in Lawrence, where the paleontologist and arachnologist teaches at the University of Kansas Paleontological Institute.
"They are in the bathroom under my sink in the cupboard," said Selden, a professor of invertebrate paleontology, or fossil spiders. "The problem is you leave a towel on the floor and it will scurry under there. In the morning, you pick up the towel and it may be on it."
But Saupe, 27, said, "I love spiders. ...Think about their ability to construct complex webs and catch food. It's pretty amazing."
While scientists are relatively blase about the dangers of the brown recluse, those who have been bit are not.
Jill Hardesty, now 47, encountered one when she was 6 and living in an old house in rural Missouri.
"It got me," said Hardesty, an editor at the University of Kansas Paleontological Institute and still has the scar.
At first, her parents thought a red, quarter-sized lesion on her thigh was a boil, but when red lines began to crawl up her leg, they knew it was more serious.
"I remember getting injections into the site and I still ended up losing quite a bit of flesh," she said. "I still have a divot on my thigh.
"I have always been creeped out by spiders," Hardesty added. "I still shake out my clothes and my husband shakes his shoes out. I tell the kids [19 and 16] to check the bed before they crawl in if it's been dormant for a week or so.
"We are pretty vigilant."