Houghton discovers potential caddisfly species

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Houghton discovers potential caddisfly species

 

Professor of Biology David Houghton studied some of the insects that live in pristine glacial bodies of water. David Houghton | Courtesy

While slogging through a glacial lake in his one-person raft, Professor of Biology David Houghton spotted a tiny waterfall.

The water fell clear, harboring just the kinds of insects for which Houghton had been looking. One of them, he thinks, was an undiscovered species.

“An untrained eye would say, ‘That’s a stick,’ or ‘That’s a bug’ or something. I’m trained enough that I can look at it and say that’s Ecclisomyia; I think that’s a new species,” Houghton said. “But I have to get it under the microscope to really find out for sure.”

Houghton spent his summer researching rivers in Juneau, Alaska, studying aquatic insects to compare untouched environments with polluted ones. Aquatic insects, particularly caddisflies — of which Houghton said he may have found a new species — are good indicators of water quality because they’re sensitive to pollution.

Studying insects provides information about the health of the aquatic environment, which helps explain how to maintain its health.

“We want to be able to assess the environment because if you can assess it, then you can fix it,” Houghton said.

The day he discovered the waterfall, Houghton had been paddling around Mendenhall Lake for an hour, looking for clean water among the glacial silt, water so thick Houghton could see no more than three inches deep.

The waterfall cleared sediment from a little pool, which he found teeming with insects. At least 134 species of caddisfly live in Alaska, and Houghton may have discovered one more.

Most of the identification process is morphological, comparing the physical description of what he found to that of previous species. Another form of analysis is more quantitative: By running samples through the biology department’s gene sequencer, he can compare its DNA sequences to other species and find the percentage of difference. But he said it’s hard to tell how big of a genetic difference would distinguish it as a new species.

“It’s not as clear cut as non-scientists like to think,” he said.

If he determines the type of caddisfly to be a new species, he gets to name it. He’s thinking Ecclisomyia mendenhalli, after the lake in which it was discovered and the Mendenhall Glacier that feeds it.

At Hillsdale, Houghton applies his field experience through classes he teaches at the college’s G.H. Gordon Biological Station in Luther, Michigan, where he introduces students to scientific study extending beyond the classroom.

“I’ve taken ecology with him up at the biostation, and that was a great opportunity because we got to spend a lot of time outside of the classroom, on the lake and in the woods doing reptile research,” senior Jon Coote said. “It was just really fun to apply classroom biology to field biology.”

For the past 10 years, Houghton has studied aquatic insects from pristine, unpolluted habitats in Michigan, Minnesota, and Wisconsin. During research in Minnesota, Houghton built a predictive model that correlated the number of species of caddisflies with levels of habitat disturbance.

He’s been almost everywhere in each of those three states, he said, so before his trip to Alaska he was “kind of running out of unique, cool places to study.”

He spent his sabbatical there last year, and he returned this summer to continue his work.

“After one summer I felt that I still had more to do,” Houghton said.

In June he arrived at Juneau, a city of decent size that is also close to the wilderness. Some days he would grab his blue packraft—a 20-pound inflatable boat that can fold into a backpack—and find a trail, paddle through a river, find another trail, and continue to wander until he found something new.

“To me the cool part is: I’m in the capital city of Alaska in a lake viewed by hundreds of thousands of tourists a year, but I paddle for an hour and I found this oasis habitat that I don’t know if anyone’s ever looked at before, finding new species of critter,” Houghton said. “For someone like me who thinks he was born five generations too late, it’s nice that there’s some of these places still left in the world.”