The Ants Go Marching One By One

Lizzie Martinez


Senior reporter


To the untrained eye, all ants look alike: six legs, lots of eyes and a few feelers. But after an entire summer of observing ants in the wild, sophomore Ben Edmonds can distinguish between dozens of ant genuses.

“We had to be able to look at the ant in the field and tell what genus it was,” Edmonds said. “We got pretty good at picking up the ant, holding it up just right and being able to name it.”

 Though ants may not appear to be the most important research topic, they are actually an important part of the ecological system.

Assistant Professor of Biology Chad Tillberg said he has always been interested in ants, which led him to this research.

The summer also led to the opportunity to present research at the Murdock Conference at the University of Puget Sound on Nov. 7 and 8, giving the students hands-on experience, Tillberg said.

“[Ants are] small, but they have a large impact,” he said. “If you want to understand how a particular ecosystem works, ants are a good place to start.”

Tillberg and four students, Edmonds, junior Erik Grimstad and seniors Sara Gerusing and Alex Freauff, spent the summer roaming Oregon state parks collecting ants, conducting experiments on them and analyzing their behavior. They looked at one genus in particular.

The object of interest was a certain type of ant in the genus tetramorium, which is not native to Oregon and labeled an invasive species. The group sought to understand how this non-native ant impacted the population and behavior of the native ants.

Before the group could begin analyzing data, they had to collect lots of ants. The techniques used involved pitfall traps and a contraption known as the pooter, which allowed the students to use a tube and their breath to suck up the ants into a collection tube and then shoot the ants into vials of ethanol to preserve them.

In addition to collecting ants, the students also conducted experiments to see which ants were best at
foraging for food by setting up baits.

Working with the ants didn’t seem to be the most interesting research for Edmonds, but he opted for it after considering his other option: a summer job.

“I wasn’t excited at the beginning,” he said. “But I was pleasantly surprised.”

Each student had a different focus during the summer. Freauff examined the position of ants in the food chain. He analyzed whether the tetramorium ants were closer to being herbivores or predators.

Freauff is planning to study dentistry after graduating, but he said the research experience was still valuable.

“It was a good resume builder,” he said. “It shows being able to work in a group setting, focus and keep track of multiple things at once.”

Because the research required collecting samples of ants and the surrounding plant and animal life in a variety of locations, the team traveled to all parts of Oregon. They camped at different state parks for two to three days each to collect samples.

Tillberg, Edmonds and Freauff each said camping and seeing new parts of Oregon made the summer enjoyable.

Though the conclusions are not final, and data from the labs are still coming in, Tillberg said the research has been enlightening.

It turns out the invasive species is more sensitive than suspected. The tetramorium ant only dominates in areas with high human use. This is because the ant prefers humid conditions, which humans replicate with sprinklers. Where the ant does invade, it dominates the native species.

The analysis will be important for people who work in agriculture, such as farmers, state park workers, ecologists and agriculturists.

After a summer of working together, Edmonds, Freauff and Gerusing will accompany Tillberg to Argentina in January. The team will spend a month studying the largest ant in the world.

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