Watch out Flathead Valley, the hobo spider is on the prowl. But unless you’re a fetching female hobo, the infamous spider isn’t looking for you.
August is the mating season for the mature male arachnids, which is why some valley residents may be seeing more of them in or around their homes.
“It’s very normal for this time of year, after we’ve had a month or so of hot weather,” said Cody Jones, co-owner of American Pest Control of Montana in Kalispell. “Males are running all over, and the females are setting up camp.”
This year, Jones said, things are actually running slightly late, and the valley is just moving into the thick of hobo season. Two years ago, when the area experienced more hot and dry weather, the spiders were out in full force. So far, he said, this year hasn’t been much worse than last.
“I wouldn’t say we’re booked, but we’re certainly staying busy,” Jones said, and added that he receives several calls a day to get rid of the pest.
Hobo spiders, or Tegenaris agrestis, are particularly elusive creatures. They’re adept at hiding, Jones said, because they fear humans want to eat them. They avoid people at all costs. In addition, the males are hunting spiders, so they move through an area very quickly in their pursuit of food.
“If you have a male in the house, he’ll only be there a day or so,” Jones said. “He’ll hobo his way elsewhere”
Exterminators find it tough to get the toxic chemicals into the hobos since they’re always on the move, and they walk on the tips of their feet, like a ballet dancer. Jones said treating a house takes care of the spider’s food sources.
Dan “the bug man” Keyser, a structural pest specialist with Complete Pest Services in Kalispell, said hobos can be found just about anywhere in the valley right now, although they’re a little bit more prominent in town, and they can infest themselves in certain neighborhoods.
Hobo spiders, introduced to Seattle from Europe in the 1930s, show up most frequently in window wells outside of basements and in other low areas around a house, said Ruth O’Neill, an insect diagnostician at Montana State University in Bozeman. Although they don’t climb very well, she added, they can come in through vents and gaps.
The spider is one of many species of funnel-web spiders, most of them harmless, which build silky mats of webbing with a funnel in the center for trapping their prey, she said. They are yellowish brown with black hairs, and sometimes have a herringbone pattern on the top of their stomach.
The legs are long and unmarked, and Keyser said they are about the size of a silver dollar.
Adult spiders have long leg-like structures on the front of their body called pedipalps, O’Neill described, which look like boxing gloves on the males. Both sexes have poisonous fangs, which are concealed underneath their heads.
Flathead County Agricultural Extension Agent Pat McGlynn said most of the spiders people bring into the office are not actually hobo, but its close cousins. The differences can be distinguished with a hand lens.
“If it has any kind of stripes down its back, it’s a cousin. If it has little dark coloration around the joints, it’s a cousin. If its fingertips, or palps, are pointed, it’s a cousin. If they’re orangey colored, that’s another cousin,” she said. “It’s very hard to tell. It’s easier to tell what’s not a hobo than what is a hobo.”
O’Neill said hobos don’t go after people, but they will bite if trapped in clothing or provoked. A bite can cause red blistery lesions on the skin, and a severe headache is the most common complaint.
“It certainly requires a doctor’s attention, but it’s not life threatening,” O’Neill said.
McGlynn agreed that the hobo spider is not aggressive, and someone might only get bit if, for example, they reach for a coat that’s been in storage, or accidentally roll over onto one that has crawled into the bed sheets.
“It kind of depends on your luck,” Jones said. “A lot of hobo bites are a dry bite, where they don’t inject the full venom.” He said hobos won’t waste their venom on something that’s not food.
There are a few things valley residents can do to keep their homes hobo-free during the breeding season.
O’Neill recommends doing a thorough house cleaning and vacuuming carefully. “Look for gaps and seal them up,” she said, and if it’s an older house, she advises hiring an extermination specialist, not to spray, but to find the gaps you may not know about.
“I don’t like the idea of spraying insecticides in my house, I don’t think it warrants that,” O’Neill said.
Keyser said hundreds of his customers can testify that insecticides work in getting rid of the hobo, although it may take more than one treatment. And his service is affordable, he added.
The most important way to get rid of hobos, McGlynn said, is competition with other spiders. Spraying eliminates the food, which actually increases the number of hobos.
“It’s better to let nature take its course,” she said.