Biology professor Sarah Boyer took three students to the Australian rainforest to research some unique Australian fauna on their own turf. Hannah Wiesner ’14, Domi Lauko ’14, Caitlin Baker ’12 and Boyer were there in search of mite harvestmen—tiny relatives of the daddy longlegs. Because the various species of harvestmen rarely travel further than 50 kilometers from their birthplace, charting where they are found reveals secrets about evolution over the ages.
For Baker (St. Louis Park, Minn.), this was her second summer doing fieldwork in the Wet Tropics World Heritage Area of Queensland, where the old growth rainforest dates back to the time of the dinosaurs.
“Whenever we would find a mite harvestman, we’d take a GPS reading. When we brought it back to the lab at Macalester, we identified the species,” explains Baker. The remainder of the summer would be spent identifying the species by morphology (physical form) and by DNA. Zach Popkin-Hall ’13 (Vienna, Va.) was also part of last year’s research trip, the first of a four-year project funded by the National Science Foundation and augmented by Macalester research funds.
As first-year students, both Wiesner and Lauko took Boyer’s course, Biodiversity and Evolution. At the time they never dreamed of joining their professor for fieldwork in Australia, but after attending the fall-term information session where professors discuss their research projects, both quickly applied for Boyer’s project.
“It was great to spend two weeks in the rainforest,” says Lauko, who now lives in Milwaukee, but comes from Hungary. They covered many miles, sifting through the leaf litter on the forest floor to collect specimens, occasionally crossing paths with a wallaby, a platypus, or a cassowary (a blue-headed bird that can grow as tall as six feet). “The environment was so interesting. On the first day someone pointed out a spider as big as my hand, sitting about a foot from my face!”
“The environment was so interesting. On the first day someone pointed out a spider as big as my hand, sitting about a foot from my face!”
“We learned lots of fieldwork techniques,” says Wiesner, who hails from Madison, Wis. “Sitting at Birthday Creek, looking up at the rainforest, I couldn’t think of anything I would rather be doing. It was exactly what I had hoped for—and better.” Back in the lab for the remainder of the summer, the focus is on the molecular work—extracting DNA for identification and using the Scanning Electron Microscope to examine morphology of the specimens.
“When we started this work, there were only five species of mite harvestmen identified in the Wet Tropics; now we know of 15,” says Boyer. “The area was wet, but now it’s dry, so there was some extinction. We’re using distribution data and looking at precipitation and temperature to construct a model of where they live and how the range of the group has changed.”
In July, Boyer and her students attended the annual Evolution Conference in Ottawa where Baker and Popkin-Hall presented posters about the research. They are also preparing a manuscript Boyer anticipates will be published in a professional journal.
Baker extended her research experience into her honors project. The day after successfully defending it, she presented at the Minnesota Academy of Sciences and received the award for the best talk. While the others will be continuing their careers at Macalester, Baker has graduated and now works as a research technician at the Smithsonian Museum of Natural History in Washington, D.C.