Many students and researchers at the University of Vermont use the week of spring recess to relax and unwind, spending time away from campus, skiing on what remains of the winter snow or hiking before mud season mucks up the trails. Others remain and work on campus, studying and continuing their research. 

But two researchers — neuroscience undergraduate Sof Antelo (‘26) and Sara Helms Cahan, Professor of Biology and the university’s Associate Vice President for Research — spent their spring recess in the sun-bleached sands of Arizona and southern California. And instead of admiring the grand vistas and mountain ranges that extend for miles along the horizon, Antelo and Helms Cahan were looking down, focusing on the microscopic mountains of ant hills.

Veromessor pergandei — commonly referred to as the desert seed harvester ant — is native to a broad swath of southwestern North America. Like other ants, the thousands of workers in the colony work together to share resources and energy to help their mother raise the babies. “That’s referred to in biology as ‘eusociality,’” Antelo said. But at the very beginning, there is no colony at all, just a young queen-to-be trying to find a good spot to dig a nest and raise her first worker daughters. And it is at this stage that these ants are unique, presenting an evolutionary puzzle that Helms Cahan has been working to crack for the last 30 years. 

“When queens found colonies, they can do it on their own,” Antelo said. “But they also have the option to form a queen group, and work together.”

That peaceful cooperation may not last, however. “In some cases, after the queens have established the colony and worker ants begin to emerge, the queens suddenly turn on each other and fight until only one queen remains,” Antelo said. But what drives a queen to be aggressive, or social, or a little bit of both? 

“That’s the question,” Antelo answered. 

Neurology and Biology

While Antelo approaches myrmecology — the study of ants — as a way to study how the brain guides behavior, Helms Cahan ­— who has been studying these ants since 1994 — works with these insects to understand the evolutionary biology of social behavior. During this trip they were capturing the harvester ants in distinct zones, on the hunt for genetic differences that could explain why queens behave so differently.

They began their trip in the Sonoran Desert in Arizona, where the harvester ant queens typically flip from social grouping to lethal aggression.

“In Arizona, you enter an area of the Sonoran Desert that receives monsoon rains in the summer,” Helms Cahan said. “This leads to a lot of moisture and an abundance of seeds that makes continued cooperation unnecessary, meaning an aggressive reduction from a group to a single surviving queen.”

Meteorological and topographical changes occur between Phoenix, where Antelo and Helms Cahan first started their research, across the Colorado River into the Chuckwalla Valley, in southern California. At a field site near the small town of Chiriaco Summit, desert seed harvester ants are never aggressive, maintaining colonies with many queens throughout their lives. 

“They do this to pool their resources so they can make it through hard times. More queens means more daughter workers to grow the colony, who can dig deeper galleries underground to stay hydrated and send out more foragers for food,” Helms Cahan said. “These places are hotter and drier in the summer and the worse the conditions are, the more queens band together and stay together.”

Even farther west, where the plateau drops into the Coachella Valley and winter rains from the coast just manage to reach the edges of the desert, behaviors shift again, and queens avoid each other altogether. 

The Search

Each day — beginning around seven in the morning — Helms Cahan and Antelo would visit a site and split up, each holding a notebook and markers, some simple excavation tools, small vials filled with ethanol to capture the ants, and a handful of pink flags to mark the hills from which they collected. Back at whichever hotel they were staying, Helms Cahan and Antelo would organize their day’s collection. 

Working quickly and efficiently, the two would replace the old ethanol with new in the vials to preserve the ant’s DNA. x

“Even though the ants are small, they still expel water from their body when they enter the ethanol, which would degrade their DNA,” Helms Cahan said. “Replacing the ethanol ensures the DNA will be as preserved as it can be.”

Back at UVM, Antelo uses a combination of genomics, the study of variation in DNA sequences, and transcriptomics, the study of RNA molecules, to analyze the queens, specifically their brains. 

“Ultimately, what we want to do is observe in that exact moment where a queen could either be cooperative or aggressive. What is going on in their head?” Antelo said. “Hypothetically, we could see a chunk of genes that are being expressed at a really high level in the cooperative queens and at a really low level in the aggressive queens, or one version of a gene that occurs in social populations but another version where queens are solitary. Those genes are prime candidates to be involved with cooperation.”

For Helms Cahan, the field trip is both an opportunity to share her love of science with a student eager to learn, and an investment in the future.

“Collections like these are a long-term resource that enable us to ask new questions as new students come in with different interests,” Helms Cahan said. “And new technologies allow us to answer questions that were impossible to address before. Every field collection is designed for a focused purpose, but typically yields ten times that in research discoveries over time because we can return to the physical specimens again and again.”

Little Ants, Little Questions, Pure Research

Some research — both in labs here at UVM and across the country — is guided by an end goal: a novel solution to a pressing problem, or an innovation to spin out into a product through technology transfer. Other research — basic, or pure research — is more simply focused on expanding knowledge and furthering a deeper understanding of a particular subject. For Antelo, it’s all about that discovery, the knowledge expansion. 

“It’s a really central question. Are you conducting some research to do something or to understand something?” Antelo said. “Because sometimes experiments and projects exist purely to understand what’s going on. I think a lot of science is exploring different aspects of the world around us but discovering these little questions and sharing the answers with the world.”

Helms Cahan sees a direct connection from basic research to real-world applications.

“The goal of fundamental research is to reveal general principles of how things work, which are interesting in their own right but also give us the baseline knowledge we need to solve applied problems, from environmental science to biomedicine,” Helms Cahan said. “For example, it is a lot easier to figure out how to cope with a warming climate if you've studied how organisms that already live in harsh environments like deserts manage to survive. And the brain of an ant is a great model for understanding how social behaviors are regulated, which we can then use to guide research into neurobiology of human social interaction disorders.”

Throughout the entire experimentation process — extracting ants from the California desert, analyzing their DNA, knowing what gene causes which action, discovering the foundations both neurological and biological of social behavior, and more — Antelo is discovering what it means to be a researcher. “In my eyes, this is science for the sake of science.”