University of Idaho researchers uncover hidden biodiversity in the sky islands of southern U.S. and Mexico

University of Idaho doctoral student Karina Silvestre Bringas and her advisor in the College of Agricultural and Life Sciences, Chris Hamilton, spent a month hiking unexplored areas of “sky islands” in search of undiscovered tarantula species.

Spanning from southeastern Arizona and southwestern New Mexico into northwestern Mexico, the Madrean Sky Islands aren’t islands in the traditional sense — they’re remote mountains covered with Madrean pine and oak forests, isolated by harsh deserts rather than water. And they are considered hot spots for biodiversity.

In support of their groundbreaking research, Bringas and Hamilton earned the prestigious Howard Hughes Medical Institute Gilliam Fellowship, which is awarded annually to graduate students and their advisors who advance equity and inclusion in science through their work.

The pair learned they’d been accepted for the fellowship in spring 2023 and are a third of the way through the three-year Gilliam Fellows Program. U of I is allowed a single entry per year for the fellowship and had never previously submitted a winning application. Bringas and Hamilton, who were nominated by U of I Vice President for Research and Economic Development Chris Nomura, will share $53,000 toward personal development and fellowship-related training.

The program will offer Bringas lessons in advancing equity and inclusion in science, in addition to opportunities to present her research at conferences. She also gets to present her project annually at a September symposium the fellowship organizes for its active recipients. Hamilton, an assistant professor in the Department of Entomology, Plant Pathology and Nematology who specializes in the biodiversity of moths and spiders, will attend a conference in 2024 hosted by the fellowship, focused on teaching with equity and inclusion in mind. The funding will also support Hamilton’s plans to bring accomplished scientists of Indigenous ancestry on campus to inspire U of I students from underrepresented populations.

Bringas earned a bachelor’s degree in biochemistry from San Diego State University before pursuing her doctorate in entomology at U of I. She’s a participant in the university’s Bridge to Doctorate Program, which provides funding for Indigenous doctoral students. Bringas is indigenous to southern Mexico.

During a pair of two-week trips to explore the Madrean Sky Islands, Bringas helped find about 10 previously undescribed tarantula species. She’s ventured to about 15 of the 65 sky islands, focusing most of her search time on the Mexican side.

“When we came in, we believed there would be at least one endemic tarantula species per sky island, especially at the higher elevation ones,” said Bringas, who plans to pursue a career as a science teacher or professor. “We’ve been to so many of these mountains already and there are still so many to go, and we’ve been finding a lot of tarantulas that have not been described before.”

Hamilton started his search for tarantulas in the Madrean Sky Islands after joining U of I in 2018, and the project gained steam a couple of years later when he received a grant through the National Science Foundation’s Faculty Early Career Development Program. He’s visited more than 30 of the sky islands, initially focusing the search on the American side, where there’s ample access from federal lands. More recently, his project has been granted unprecedented access to private lands on the Mexican side, with help from several collaborators in Mexico.

“On the Mexican side all of the land is private,” Hamilton said. “So far, we feel like based on talking with landowners and ranchers, we’re the first people they’ve ever had up in their mountains.”

The next major thrust of the research project will be sequencing genomes of several tarantula species from the mountains and surrounding desert. They’ll focus on genes related to physiology and evaluating genomic changes.