Tue, July 16

Venomous caterpillars in the Verde Valley? What you need to know
It ‘looked like Donald Trump’s hair’

Simpson shows the aftermath of brushing up against a venomous caterpillar recently during a bike ride at Cottonwood’s Riverfront Park. Photo courtesy of Tal Simpson

Simpson shows the aftermath of brushing up against a venomous caterpillar recently during a bike ride at Cottonwood’s Riverfront Park. Photo courtesy of Tal Simpson

COTTONWOOD -- Tal Simpson was riding his bike through Riverfront Park last week when he was stung by an unusual caterpillar.

Simpson, who lives in Cottonwood, regularly bikes through the park and back. This time, the ride back was slightly overgrown with foliage, and Simpson brushed against it during his trek.

At the end of his ride, Simpson was near the playground when he looked down at his sleeve and noticed something that he said “looked like Donald Trump’s hair.”


Puss caterpillar. Photograph by Donald W. Hall, University of Florida Featured Creatures.

The creature was a fuzzy, yellow-brown caterpillar, which Simpson promptly knocked off his sleeve. It was then that Simpson felt a burning sensation.

“I knew as soon as I was stung that something was bad,” Simpson said.

He Google searched “venomous caterpillars” and came across his main suspect – the asp or “puss” caterpillar.

Simpson said when he got home, he experienced 24 hours of the most excruciating pain he had ever felt.

“[My wife and I] called poison control, the hospital – nobody had heard much about these – they said take Benadryl and make sure he’s breathing,” Simpson said.


Cell photo image of the caterpillar that stung Cottonwood’s Tal Simpson recently. Photo courtesy of Tal Simpson

Research Professor Dr. Neil Cobb, at Northern Arizona’s biology department, said it was likely not the famous asp caterpillar that has made headlines across the United States, but rather a relative within the same genus.

“It was highly unlikely that it was a puss caterpillar – the puss caterpillar is not normally found west of Texas,” Dr. Cobb said. “There are three other related species in Arizona, and to my surprise all Arizona records for these species are restricted to southeast Arizona, so this would be the farthest north record for these moths,” Simpson said.

The “electric-like” pain Simpson experienced spread from his fingertips to his shoulder. Physical contact with the caterpillars is enough to feel the ill effects.

“They don’t bite – it’s their hairs. Their hairs inject a poison into a person. A lot of caterpillars [do this], and also spiders do too. He probably got these hairs stuck in him,” Cobb said.

As for future encounters, Simpson plans on steering clear of potentially meeting a flannel moth caterpillar again.

“I won’t be riding or hiking the trails near the brush until December. It was bad, I wouldn’t wish it on anyone,” Simpson said. “It made me go through a little bit of everything – fever, headache, respiratory.”

What to do if you’re stung

As for keeping safe from such caterpillars, “Any insect that is brightly colored or has lots of hairs anyone should avoid,” Cobb said.

If encountered, the larvae should not be handled, despite their cute, fuzzy appearance.

Medical toxicologist Dr. Frank LoVecchio at Banner Health in Phoenix said there is minimal treatment available for caterpillar stings.

“Here’s what usually happens from a caterpillar: nothing. The [caterpillars] I’ve seen in Arizona have those hairs and they hurt for a while. We usually tell patients to take Benadryl and you should feel better in a few hours. Whereas a true asp will really, really hurt,” said LoVecchio. “What we usually do is treat them for pain and that’s about all. There’s not an antidote or anything like that.”

LoVecchio said that sometimes people are allergic to Benadryl and may require other medication.

“If the sting is from the hairs, what you can do pre-hospital is put a piece of cellophane tape on the sting and rip it off,” LoVecchio says. This will help remove any hairs that may be in the skin. An ice pack and hydrocortisone cream will also help the ease the pain.

Arizonan relatives of the asp moth

While the asp caterpillar has made headlines across the United States, the caterpillar Tal Simpson encountered was most likely a distant relative of the infamous creature. True asp moths have not been documented west of Texas. Simpson was likely bitten by one of the three species under the same genus that live in Arizona, which have not yet been documented this far north. The three species are:

• Megalopyge bissesa, Bissesa Flannel Moth

• Megalopyge crispata, no common name

• Megalopyge lapena, no common name