The Amazing Spider Hunters
Susan Riechert leads students in arachnid research throughout the American West
She crept through the dewy grass, stepping high and slow. When the glisten of the funnel web caught her eye, she crouched down and pulled out a snap cap vial. She reached inside with her tweezers and plucked out a harvester ant, which has the most toxic venom of all of the insects. Snapping the vial shut before the other ants escaped, she leaned over the web, dropped the angry ant and waited. When the spider ventured out to claim its harvest—swoosh! She scooped up the whole scene—dirt, web, and spider—and plopped it into a large, plastic box. Her final step was to deliver the captured spider to her faculty mentor, Susan Riechert, who identified each spider and placed it into a little plastic container, like the ones restaurants use for take-out salad dressing.
This is how Jenn Bosco, a graduate student in ecology and evolutionary biology, spent her spring break, collecting specimens of Agelenopsis, commonly known as the grass spider. The team of UT scientists from included one professor, one grad student, and two undergrads who traveled nearly 3,000 miles across Texas, New Mexico, and Oklahoma hunting for these elusive spiders.
Riechert, a Distinguished Service Professor in the Department of Ecology and Evolutionary Biology who has studied spiders for four decades, knew where to find them. Her goal was to find five species and explore their differences related to mating. They all look the same, so how do the species maintain their distinctiveness?
“We want to better understand how evolution works,” Riechert says. “This study involves species isolation, how species maintain their separate identities.” It’s about the selfish interests of the individual, too. The goal is to get as many copies of one’s genes into the next generation as possible. That means finding the right mate in the same species and possessing “good genes.”
Over the years, Riechert has mentored more than thirty graduate students and dozens of undergraduates in her research lab at UT. The lucky ones, the ones who perform well in the lab, sometimes get to join her in the field. They get one-on-one time with their favorite, top-notch researcher, renowned among her peers, whose academic papers on spider behavior from as early as the 1970s are still widely cited today.
That’s the good part of these trips. The bad might include lying awake in a tent in a sleeping bag rated for 40 degrees when the temperature is 16. Evolutionary biology is dictated by nature, and nature isn’t always kind. On this trip, it would turn out to be too cold to capture some of the species.
Moving out of the mountains, a healthy population of spiders was finally found at Foss Lake, Oklahoma, where an alternative project idea was hatched. The goal was to find a question that the undergraduates, Evan Beierschmitt and Austin Dillon, could explore and, hopefully, publish a paper on. They would gather spiders from distinct habitats and compare them to each other. Were different species favored at this site, as Agelenopsis here occupied both forest and grassland habitats, or was it one species in which populations had diverged into different ecotypes?
Experience, publications—the benefits of undergraduate students literally getting their hands dirty with research include strong résumés, which often impact admissions to prestigious graduate schools and medical schools. For graduate students, working with a respected behavioral ecologist like Riechert can enhance their careers immeasurably. Back at the UT lab, Bosco is studying the behaviors and courtship dance of the captured males and helping Riechert with genetic studies to be completed on spider personality and temperament.
“Among other things, I’m interested in the genetic basis of aggressiveness,” Riechert says. “Everything I can do with spiders, we can do with mammals. It’s just quicker, and I can get huge sample sizes.” They came back from spring break with 500 specimens.
“This research furthers many areas, including the evolution of game theory,” Riechert says. “It’s a good example of how everything’s interconnected.” She notes that her research interests have evolved over the years and suggests that’s the beauty of basic research. It allows her to “research the unusual,” to teach students about the scientific research process, and to give them hands-on experience.
For example, the recent spider-hunting trip is one of several to gather laboratory populations of fourteen species of the genus Agelenopsis, which are difficult to distinguish by their biological form and structure. Riechert’s team of student researchers will study the spiders’ courtship signals and mating rituals to understand the mechanism of reproductive isolation, which is central to the speciation process.
“Mentoring students is something I really enjoy,” she says. “It gives the students a sense of identity and community. Most who do well end up in grad school, med school, and continuing education beyond undergrad. That’s what we want.”