Thousands of Caterpillars

Observation: This post was prepared in collaboration with Julia Pinnix of King Salmon. She writes that on the northern Alaska Peninsula, there were five reports in August this year and one from early September 2012 describing the presence of thousands of black and gold caterpillars, likely a species of tiger moth. One report said, “The tundra was thick with fuzzy caterpillars… There were millions of them.” Two reports come from Lake Clark National Park, one from Katmai National Park, and three from Becharof National Wildlife Refuge (including the one from 2012). They were photographed on willow bushes and scattered across the tundra. Little work has been done on the Alaska Peninsula to identify insect species. Whether these huge numbers of tiger moth caterpillars are normal or unusual here is unknown; and what impact they may be having on local vegetation is also a mystery. Mike Brubaker, ANTHC, Director Community Environment and Safety, LEO, with Julia Pinnix of King Salmon.

Photos (2) courtesy of Julia Pinnix, King Salmon, AK. To view larger images go to our Flickr URL: link

LEO Comment - Similar posts were submitted to the LEO Network in past observations. see below:

August, 2012; King Salmon, Alaska by Oxcenia O'Dimon, LEO for Joni O'Dimon, local resident, entitled, "Caterpillars in King Salmon," you can find it here (link).

July 21, 2013; St. Mary's, Alaska by Richard Alstrom, LEO documented a Tiger Moth. See it here. At the time Kenelm Philip with the Alaska Leipodoptera Society wrote: "This is the larva of the tussock moth Orgyia antiqua, which is widely distributed in Alaska. The ALS collection has specimens of the adults from Fairbanks and King Salmon, among other sites, and this is not a new species for the area."

August 20, 2013; Kake, Alaska by Edna Jackson, LEO posts about a spotted tussok moth. See post here (link).

June 09, 2014; Chalkyitsik, Alaska by La'ona DeWilde, LEO. There were thousand of caterpillars on the nettle covering an area of about 100 square feet. It was a mass of moving black swarm eating the plants down. We want to know if this is a potential problem to the local vegetation and if this is a native butterfly or an invasive species. See post here (link).

This post has been shared with natural resource and environmental staff at the Bristol Bay Native Association and Bristol Bay Area Health Corporation. It will also be shared with our partners on insect posts at the UAF Cooperative Extension Service.