People who come across the furry, yellow and black caterpillars with white plumes crawling around Haines should look but not touch, a Juneau scientist said.
While many people call them woolly bears, retired ornithology professor and Alaska Department of Fish and Game biologist Bob Armstrong said the bumble bee looking caterpillars are called spotted tussock moth caterpillars. Despite their bright, colorful and cuddly appearance, it’s a bad idea to handle them because, like bumble bees, they can sting.
“They basically aren’t eaten by anything so they can wander about in the open and not worry about anything except for cars and people stepping on them,” Armstrong said.
You can find armies of the caterpillars scuttling along trails, clinging to bushes by the ferry terminal and smeared along roadways in increasing numbers. Spotted tussock moth caterpillars, or Lophocampa maculata, are distinguished from woolly bears, a different genus, by their white, barbed and stiff plumes which can sting and inject toxins.
“L. maculata is clearly distinguished by white lashes on its anterior and posterior as well as black dorsal tufts. The barbed setae of Lophocampa are known to cause physical irritation or stings, and may also contain allergenic proteins,” a report on the US National Library of Medicine’s website said.
Some species of caterpillars, such as the spotted tussock moth caterpillar, can cause minor, localized skin irritation. In rare cases they can also be life threatening. The report describes a 5-year old boy in Ohio who was stung by the caterpillar.
“The child had been playing with the caterpillar for 20 minutes before sensing a piercing pain from under the caterpillar and reporting to his mother, who identified a small (red) lesion at that location. Within 3 minutes, the boy experienced (skin rash) starting at the lesion and advancing up his arm, quickly covering his entire body.”
Within five minutes the boy went into anaphylactic shock, the report says.
“It’s probably a good idea for kids not to handle them,” Armstrong said.
Similar to Haines residents, Armstrong said he first noticed the caterpillars in large numbers about a year ago. Now he studies them.
“I spent quite a bit of time looking at them and watching,” Armstrong said. “I wondered where they were going and what they were doing and I couldn’t find any place where they were going. Then I started turning over rocks and sometimes I’d find 15 cocoons under a rock,” Armstrong said.
The moths hatch in the spring. They mate, lay eggs and die shortly after. Unlike their past lives as caterpillars, the moths are hunted. Bats prey upon them. Similar to the caterpillar’s white, barbed stinging plumes, the moths have evolved a defense tactic.
During his research, Armstrong discovered that the moths make clicking sounds, which some scientists theorize disrupt bat sonar. Armstrong designed his own experiment to test the theory, but he never captured a moth.
“My goal was to get some adults and put them in a tent and I was going to use a device that gives bat clicking sounds and I was going to see how the moth reacted and if I could record the clicking the moth was making,” Armstrong said. “Maybe next spring.”
Some Haines residents say they’ve never seen the black and yellow caterpillars until recently. Others say they’ve been around for years, but the past few years have seen a sharp rise in caterpillars.
“We used to have them, just not in mass profusion,” Lee Heinmiller said. “The moths are what you see most of. You don’t see the caterpillars that much. It kind of varies year to year.”
Armstrong took a seven-hour video of a spotted tussock moth caterpillar spinning its cocoon on a rock. To watch a time-lapse version of the video visit http://www.naturebob.com/spotted-tussock-moth. The video will also be linked from this story on the Chilkat Valley News website and Facebook page.