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No Worries About Giant Brown Spiders

You might have noticed there’ve been a lot of really big, kind of scary, brown spiders running around lately. It’s not your arachnophobia making you paranoid; late summer into fall is mating season for the arachnids. 

Don’t smash them, says Melissa Scherr of the Northwest Entomological Research Center, because what you are seeing are male spiders that are horny, looking for mates and are pretty much harmless. Normally the spiders are reticent but she sees in their search for females the males go “full bore until they find what they need” and probably won’t slow down until we get a cold spell.

Spiders trigger a primordial fear for humans, Scherr says. Despite her doctorate in entomology, even she has a second or two of shuddering when she encounters a spider, with its “creepy walk and demeanor,” but she says the key is to get past that shudder and override the fear. The brown spiders you are seeing might be anything from a barn funnel weaver (Tegenaria domestica), to giant house spider (Tegenaria gigantia) or a hobo spider (Tegenaria agrestis). The “agrestis” in the hobo spider’s name doesn’t mean aggressive but has to do with fields since in their native Europe, they are found primarily outside. 

It’s hobo spiders Oregonians tend to fear because of the belief that they have a venomous bite that causes necrosis, but Scherr says first of all spiders like this rarely bite us. The way their jaws are shaped doesn’t lend themselves to biting humans. “It’s kind of like you trying to bite a giant, inflatable beach ball,” she says. Also, Scherr says, there’s no direct evidence that a hobo spider bite has caused necrosis in a human. Even better, no hobo spiders have been documented in Oregon south of Corvallis, and there are no brown recluse spiders in Oregon at all, according to Scherr. The state does have black widows, but with their black bodies and red hourglass on their abdomen, the females are not easily confused with harmless brown spiders.

If you did get bitten by a spider, Scherr says it is possible to have an allergic reaction, in the same way someone might be allergic to bees, but generally when someone thinks he or she has been bitten by a spider it tends to actually be a mosquito bite or something else. 

Orb weavers, Scherr says, are even more harmless. They like to live outside, not in homes. But the moment a human walks into a web, “It’s like zero to ninja,” she says. Like their orb-weaving counterparts, house-dwelling spiders help you out by eating bugs, including silverfish and the bed bugs that are becoming a problem across the country and really do bite humans.

When you see a big brown spider skitter by, “It’s OK to be afraid of it for the first second,” Scherr says, but then “let your curiosity take over.” If you do want to get over your arachnophobia next time you see a big spider, she recommends killing it humanely by putting it in the freezer then getting out a microscope or magnifying glass for a close up look to override the fear and to see the beauty of the bug. For more on identifying spiders, go to the Northwest Entomological Research Center’s webpage at nwerc.org to get links on spider identification via its Facebook and Twitter feeds.