Ryan Davis is a Utah State University Cooperative Extension insect diagnostician who says the bite of a hobo spider may not cause flesh-eating lesions as once thought.

“The bulk of research is coming out of the University of California-Riverside,” said Davis. “Richard Vedder has started looking into the issue of necrotic lesions and hobo spider bites. He’s determined that the evidence is circumstantial at best for implicating hobo spiders.”

Judging from what comes into his lab Davis said there is a large population of hobo spiders in northern Utah. Also, he said there is no evidence supporting those who suspect brown recluse spider bites cause the flesh-eating lesions.

“The brown recluse range is more in the Southeast and Midwest regions of the country,” said Davis, “and it does not even extend into Utah.”

Davis said people tend to be afraid of spiders in general and often like to blame them for certain things because of fear.

“The reality is that most people don’t actually see the spider biting them nor are they able to collect the spider and have it identified. As far as actual verified bites go we just don’t have that evidence.”

Davis said in Europe, where the hobo spider originated, it is not considered to be of medical significance.

“New research done comparing the venom from Europe to the venom of hobo spiders in the United States indicates that the venoms are not different.”

At this point, said Davis, research is unable to determine whether hobo spiders are poisonous.

“One of the most critical aspects of this research is to point out that doctors may be diagnosing necrotic lesions as hobo spider bites when, in fact, they may be caused by something much more serious such as a cancerous ulcer or a viral disease or something bacterial. There are about 40 conditions which can cause necrotic lesions.”