Entomologist Thomas Werner has studied fruit flies from coast to coast. But his most unusual discovery yet was closer to home.
Armed with a banana-baited live trap and a strong desire to disprove gaps in species distribution maps, the Michigan Technological University professor of genetics and developmental biology set out on Hancock’s Maast Hite Public Recreation Trail. I found one specimen of the species Drosophila narragansett. , Michigan.
Researchers suspected that the silver-faced fruit fly, Drosophila narragansett, might be extinct. “What’s surprising is that despite its wide range, it doesn’t seem to have been collected in the last 60 years,” Werner said.
The expedition that discovered the elusive fruit fly was completely unplanned. It began with a fascinating research paper in the hands of Werner, an educator who has spent his career raising awareness of the scope and importance of Drosophila.
He co-authored two volumes of the North American Drosophila Encyclopedia. Volume 1 focuses on Drosophila melanogaster in the Midwest and Northeast. Volume 2 lists species from the Southeast. His co-authors are John Jainike, professor emeritus of biology at the University of Rochester, and former student Tessa Steenwinkel. Steenwinkel, a 2020 MTU graduate in biochemistry and molecular biology, earned a master’s degree in biological sciences from Tech University in 2021. She is currently a graduate student in Development, Disease Models and Therapeutics at Baylor College of Medicine.
A professor goes hunting with a mysterious map
Because he is one of the few experts in fruit fly identification, Werner frequently receives research papers submitted for peer review. He was on Christmas vacation in Mexico with his family in 2023 and had no intention of reading any research papers until an email request caught his attention.
But why are fruit flies important?
As Werner can attest, fruit flies are more than just kitchen pests. These are tiny genomic models that hold a mirror up to the causes of human conditions.
“Research on fruit flies is relevant to chemotherapy, cancer research, and metabolic disorders. Some fruit flies are resistant to mushroom toxins. All are related,” he said.
“You can study almost any human disease using just one species of fruit fly found in your kitchen.”
Werner is referring to Drosophila melanogaster, the species most commonly encountered by humans because they are attracted to rotting food. The small, tenacious composter is one of at least 350 known species of fruit flies in mainland North America. Werner catalogs them all.
“I thought, ‘Oh, I don’t want to review long papers right now,'” Werner said. “But when I looked closer, I realized it was written by David Grimaldi from the American Museum of Natural History in New York. He’s a great guy who writes about weird fruit flies that people don’t get to see. All of that. species that are under-researched. “
Grimaldi’s latest paper focuses on the Drosophila affinis species group. “These are small black fruit flies. Some in this group are very common, and some are less common,” Werner said. He had just spent a year reviewing the group in preparation for his third book on Northwest fruit flies, due out next year. After reading about 2,000 academic papers on the group, he felt he couldn’t say no to the review.
Werner decided to read the newspaper when he returned from vacation. But he couldn’t stop peeking. “I started reading the first few sentences and I read all this stuff all night long, reading it on my phone. It was so interesting. I was so drawn to it. I couldn’t stop reading it. I was like, ‘Oh my God. I was like, Wow, I have so many ideas! I was like, “Wow, this is the best paper I’ve ever read!” ”
Werner was particularly intrigued by the hand-drawn species distribution maps included in the paper. It marked a relatively small area just outside his backyard on the Keweenaw Peninsula, home to Michigan Technological University in the state’s Upper Peninsula, as a no-go zone for two species of fruit flies. Additionally, Werner had sighted the species in the Huron Mountains, about 80 miles east of Keweenaw, where he cataloged 35 species of fruit flies. No-fly zones made no sense.
“I wondered why anyone would draw the line below this for this common species,” Werner said.
This summer, he planned a slow trip north into the exclusion zone, dangling a banana-baited fly trap to prove the species existed. “It seemed like a small thing, just to prove my point,” Werner said. He is familiar with all the local species, so he doesn’t usually do research close to home. Or so he thought. He never expected that his casual experiment would produce a rare species. He didn’t notice anything unusual about the two flies he had captured until he returned to the lab, dosed them with ether, put them to sleep, and obeyed his urge to look into their eyes.
“Drosophila narragansett and the very common Drosophila athabasca look exactly the same, except when you pick them up and look at them head-on,” Werner explained. “My inner voice is often right: ‘Look at their faces.'”
Esterified fruit flies sleep on their sides. It is difficult to manipulate small insects and get a complete picture of their faces.
“You have to carefully lift and rotate it to see the face straight,” Werner explained. “You have to focus and go up to see it. And the first face was silver. And I thought, ‘No, no, that can’t be true. That can’t be true.’
Wondering if he was hallucinating, Werner saw a second fly, its face completely black. The contrast was clear. “I was breaking out in a cold sweat,” Werner said. “They started waking up. I cleaned them up. I started texting my collaborator John in Rochester, New York, who co-wrote the book with me and Tessa. ”
Jainike, a professor emeritus of biology at the University of Rochester, specializes in evolutionary ecology and is best known for his research on fruit flies. Seven years ago, researchers discovered an unidentified specimen of the fruit fly, Drosophila narragansett, in a compost bin in their front yard. While being transported to Werner’s lab for imaging, the specimen’s face fell into the preservative and turned black. Jaenike’s lab was able to generate a partial genetic sequence from the remains. “It was close to 97%, but it wasn’t completely clear,” Werner said.
Werner’s discovery marks the first fully sequenced specimen of this species. “My collaborator Bernard Kim, who works in Dmitri Petrov’s lab at Stanford University, recently confirmed its identity. It is indeed Drosophila narragansett!” he said.
Drosophila records and discoveries continue
Drosophila narragansett is not Werner’s first unusual discovery. He previously discovered a species of fruit fly, Amyota tessae, and named it after his graduate student mentee, Steenwinkel.
Other unique discoveries await. For three years now, Werner has been traveling from his lab every summer to document fruit flies across North America. “It’s like being in your home lab,” Werner says. “Except for the fresh air.”
This experience changed the way Werner conducted his research. “I would like to spend part of my time doing fieldwork and part of my time working in the lab. I find great joy in both activities,” said the award-winning educator. Ta. His students at Tech University and elsewhere. “It changed the way I do science.”
Werner has been collaborating with Kim on genome sequencing of Drosophila species since the two met over Zoom in 2020. At the time, Kim was a new postdoctoral fellow in Petroff’s lab at Stanford University and asked for help. Kim joined Werner this summer on fieldwork in the Pacific Northwest for Volume 3 of the Encyclopedia. So does Daniel Shakevich, a graduate student at Stanford University who is working on a documentary about the expedition.
Werner hadn’t studied his hometown’s fruit fly population for years. But he plans to return to the trails next summer.
He believes timing may be part of the reason why fruit flies, which were thought to be extinct, have never been discovered. Early summer is not the time when fruit flies are most active in this area. “August is when our produce baskets become magnets,” Werner said.
His traveling lab could extend further afield.
“There are another thousand species of fruit flies in the Hawaiian Islands alone,” Werner said. “That might be next on my list.”
Founded in 1885 in Houghton, Michigan, Michigan Technological University is a public research university with more than 7,000 students from 55 countries around the world. Consistently ranked among the nation’s best universities for return on investment, Michigan’s flagship polytechnic offers 120 schools in science, technology, engineering, computing, forestry, business and economics, health professions, humanities, mathematics, and social studies. We offer undergraduate and graduate degree programs such as: science and art. This rural campus is located just a few miles from Lake Superior in Michigan’s Upper Peninsula, offering year-round outdoor adventure opportunities.
