Aaron Ellison, Fisher Associate Professor of Environmental Studies, views science as an open-ended set of questions. "One question inevitably spawns another, leading to new areas of inquiry," he says.
Ellison should know. An expert on carnivorous plants, his research on the nutritional processes of the pitcher plant has led to a discovery outside his area of expertise. Ellison, along with students Rebecca Emerson, '01, Kirsten McKnight '03, and Samantha Williams '01, is becoming an authority on ants. In the process, the students are gaining invaluable experience in the science of fieldwork.
During the summer of 1998, while studying interactions between carnivorous plants and insects in Massachusetts and Vermont bogs, Ellison and Tuyeni Mwampamba '00 completed an intensive sampling of insects at Hawley Bog in northwestern Massachusetts. The bog, owned by Five Colleges Inc. and managed by the Massachusetts chapter of the Nature Conservancy, is used as an outdoor classroom. By setting traps (beer cups filled with water, and tuna packed in canola oil placed on index cards), Ellison and Mwampamba collected about eighty ants in the Hawley bog and sent them for identification to Harvard ant scholar Stefan Cover and University of Vermont scientist Nicholas Gotelli.
Ants are the most common prey of the pitcher plant, which is composed of hollow stalks filled with rain water. When insects are unlucky enough to fall inside, a hair-like apparatus lining the stalk's interior keeps the bugs from escaping. Some of the collected ants turned out to be a new record (scientific terminology for the first known occurrence) for Massachusetts. The final identification of the ants is not complete, but Cover believes that the ants are a new record either in the area east of the Rocky Mountains or in the continental United States.
After the ant finding, Ellison contacted the Massachusetts Heritage and Endangered Species Program (MHESP), part of the National Fish and Wildlife Service, and talked with scientists there. The agency later awarded him a grant to survey ant species diversity in the summer in Massachusetts bogs that have pitcher plants and are in excellent condition. The MHESP grant funded Rebecca Emerson's work, while the National Science Foundation enabled Kirsten McKnight and Samantha Williams to participate.
The stage was set for a summer of intensive ant collecting. In order to access the bogs, the researchers hiked through dense vegetation, most often without the benefit of trails. One false move could leave them waist-deep in muck. The students were undaunted. "Even after the 100-degree days of trudging or getting soaked in the worst muck imaginable, even after the sickening task of sucking up ant/alcohol fumes [ants were collected using a rubber hose connected to a test tube filled with alcohol], I still hope to become a botanist," says McKnight, who applied for the research assistant position soon after she learned that she had been accepted to Mount Holyoke. The daughter of a biologist, she has enjoyed helping with field research since she was a child.
McKnight focused on the botany of bogs, in addition to the ant work. Collaborating with Ellison was an important aspect of the research experience for her. "It was beneficial to work so closely with a member of the faculty who is one of the most prolific environmental science researchers I have ever met. I was able to become familiar with many of the issues and work habits that field research work entails," she says. Ellison contends that giving students the opportunity to participate in research projects as undergraduates gives them an edge. "Learning to do research is akin to being an apprentice," says Ellison. "Hearing about research in a classroom is not a substitute for learning to do research with an experienced researcher. By working one-on-one with faculty members, our students have the same opportunities to become researchers as graduate students do. These opportunities give them a head start in the competitive world of professional science."
The group visited fourteen bogs during the summer. At each site, they left traps at twenty-five locations, returning two days later to collect specimens. In addition, vegetation analyses were conducted and ants were collected in nearby forests. After Ellison taught them how to collect ants, the students were responsible for gathering more than 4,000 of the insects.
Back at the lab, Ellison and the students used diagrams of ant anatomy and reference specimens to recognize the hallmarks of individual species. They identified twenty-four different types of ants. "I can even identify ants by the shape they make after being submerged in alcohol," Emerson notes.
Ellison will spend this year analyzing data collected over the summer, focusing on whether forests and bogs have distinct ant groups; the relationship between vegetation and ant species diversity; patterns of coexistence among ants; the range of particular ant species; whether different ants have different nutritional value for the plant; and how health of the plant is affected by the type of ants it consumes. With the help of the students, he will prepare an inventory of ant species in Massachusetts bogs for a report due to the MHESP by May 2000.
While collecting ants, Ellison and his students came across many different spiders, giving birth to yet another line of questioning--the role of spiders in controlling ant species diversity. Emerson, who is taking a year off from her studies, will continue to work with Ellison, spending twenty hours a week largely on spider identification. McKnight is also sharing Ellison's lab during the academic year, performing digital analyses of the slides taken of pitcher plants. With new questions surfacing regularly, the process of scientific inquiry continues.