Grant Supports Research on Communal Behavior in Western Harvester Ants

Maya Reese, a University of Houston biology Ph.D. student, was awarded the 2018 Tschinkel Ant Natural History Research Grant. This award, for the amount of $2,500, is administered by the International Union for the Study of Social Insects in support of graduate student research on the basic natural history and biology of ants.

As the award committee noted, Reese’s application was “selected from a field of highly competitive applications,” with her proposed research “firmly rooted in a deep understanding of the natural history of her species of choice.”

Behavior of Social Insect Colonies

Reese, whose research is advised by Blaine Cole, professor of biology and biochemistry in the College of Natural Sciences and Mathematics, studies the behavior of Pogonomyrmex occidentalis, more commonly known as western harvester ants.

“My research focuses on the development of consistent behavior traits in social insect colonies,” Reese said.

Western harvester ants are an example of a eusocial species, in which the division of labor is strictly compartmentalized. These ant colonies are headed by a single queen, which can live up to 45 years. Other duties within the colony are carried out by worker and forager ants, which have a lifespan of six months to one year.

Colony Behavior Changes Over Time

A colony can live up to 45 years. During the course of its lifetime, as a colony matures and increases in size, it undergoes dramatic changes. Reese is interested in understanding how behavioral traits of a colony develop with these changes. These traits include activity levels, boldness, exploration and aggression.

To do this, Reese spends three months in the summer doing field work in Colorado, where she examines the collective behaviors of 130 colonies. By testing the behavioral traits of the colonies she can gain an understanding of how these traits vary according to colony size and age. Reese, who has been examining these colonies for two years, will also be able to gain an understanding of how an individual colony might change over time.

“We’ve found that colony behavior changes based on its size,” Reese said. “As colony size increases, variability in behavior between colonies decreases significantly.”

The reason for this decrease in variability as a function of size is still unknown. As part of Reese’s thesis project, she is conducting tests to determine what the answer might be. It could be that colonies change their behavior due to their experience, it could be that selection is acting on colonies that exhibit specific behavioral traits, or it could be a mixture of reasons.

“Ants are some of the most amazing creatures on the planet,” Reese said.

- Rachel Fairbank, College of Natural Sciences and Mathematics