Millions, perhaps hundreds of millions, of ice worms can be seen wriggling to the top of glaciers from the Chugach Mountains in southeast Alaska to the Cascade Volcanoes of Washington and Oregon during the summer months.
Credit: Scott Hotaling Hotaling's interest in ice worms began back in 2009 while he was working as a mountaineering ranger on the high elevation slopes of Mt. Rainer.
In the study Hotaling and colleagues extracted and sequenced DNA from 59 ice worms collected from nine glaciers across most of their geographical range.
Credit: Scott Hotaling The researchers predict that this deeper split into two genetically distinct ice worm groups occurred as a result of glacial ice sheets contracting around a few hundred thousand years ago, isolating worms in the Pacific Northwest from their counterparts in Alaska.
The most surprising finding of the study was the discovery of a single ice worm on Vancouver Island that was closely related to a population of ice worms 1,200 miles away in Alaska.
The research illuminates an important relationship between two of the few large organisms that inhabit North America's high elevation alpine ecosystems, the ice worm and the Gray-Crowned Rosy Finch, one of North America's highest elevation nesting birds.
information: Scott Hotaling et al, Long-distance dispersal, ice sheet dynamics and mountaintop isolation underlie the genetic structure of glacier ice worms, Proceedings of the Royal Society B: Biological Sciences (2019).