Animal Life, NSC 1307, Spring 2002

Article Review – April 30, 2002

Ash Jones

The animal being studied is the red harvester ant. The field site for this research is a natural habitat for red ant nests located on 25 acres of land, owned by Stanford University in the Chiricahua Mountains of southwestern New Mexico. The research question is to determine how individual, dim-witted ants are able to build complex nests and maintain their colonies, using a new generation of ants each year, for the twenty-year life span of their colonies.

The principle investigator is Deborah Gordon, an associate professor of biological sciences at Stanford. She has been going to this site every summer since 1981, taking along students to assist.

Her hypotheses were that individual laboring ants were specialized in some internal way to do selected tasks, and their combined work achieved the orderly functioning of the colony. Another hypothesis was that each queen ant acted as leader of her own colony. Each queen would establish her nest; give birth to generations of specialized, laboring ants; and direct the activities of the laborers.

Gordon and her students collected data by mapping the location of 300 red harvester ant nests on the field site in New Mexico. Each year, they looked for new colonies, identified colonies that died, and observed and recorded the movement of color-coded ants in and out of the colony. The researchers used fiber-optics microscopes to probe into ant colonies, and study the behavior of the queens and the worker ants. Occasionally, the team dug up a whole ant colony to bring it back to their California laboratory, so that they could observe how the nest was built and maintained.

The results of their studies were surprising; by observing individual ants and ant colonies over years, the researchers found that although the nests are very similar, the individual ants are not specialized and the colonies do not have leaders. The same ants perform many different functions over time; they usually start out by digging tunnels in the colony, insulating the tunnels with dirt, and nurturing young ants; a few weeks later, the same ants act as patrollers, then food foragers, and then protectors.

In different generations of the colony, worker ants behave differently; in the early years of the colony, the ants may fight ants from other colonies, like "adolescents," but in later years, "mature" ants just avoid ants from other colonies.

Using the fiber-optics microscope, the researchers learned that even the queen was not in charge of her colony. Her function was to produce 10,000 eggs a year, deep in her birthing chamber. Meanwhile the laboring ants build the nest, nurture the new generations of young, forage for food, and protect against invaders without any leaders. Even in the twentieth year of the colony when the queen has died, the colony lives on in a perfectly organized way for the entire year. The colony dies because no new ants were born.

These observations led Gordon to interpret the activities of individual ants to be the result of constant interactions with each other and with changes in environmental conditions. She concluded that ants do not have inherited abilities or task orientations, but rather an ability to switch tasks and be flexible, based on their interactive patterns.

She also believes that her research on ants and ant colonies may offer an important key to the development of "computer science, robotics, and artificial intelligence." For example, "packets of information traveling over the Internet …could route themselves around digital traffic jams."

This research on red harvester ants demonstrates to me the complex function of animals as tiny as ants. It is easy to think that human activity is complex, but this research shows that it is just as hard to determine how ants and their colonies function. There clearly seems to be order in nature, but how it has evolved is still a mystery. Although Gordon’s original theories of ant colony leadership and worker specialization were refuted, her research led to several, interesting results.

I was intrigued by the concept of how interactions among living organisms become the signals to accomplishing daily activities, which, on the surface, appear to be routine. For example, as the plant life, the availability of water, the temperature outside the nest, or the age of the colony changes, the activities of individual ant’s change and the future, including survival of the whole colony, changes too.

It is also neat to know that great things can be accomplished without leaders. Working together and constantly taking cues from each other, individual animals have the capacity to live very efficiently and establish orderly, functioning colonies.

Gordon also observed that while ants are usually described as perpetually busy; many were just standing around idle or carrying junk instead of food. Maybe there is an important "function" in free time.

I think this research also has application in my fields of interest, business and golf. For example, office workers and outdoor laborers are assigned different tasks, depending on things like the environment, time of year, and age of the business. When a new golf course is being created, the main work is in design, physical construction of the course, hiring capable people, and establishing inventory. During the winter, the work switches to maintenance, evaluation, and government reporting. In spring, it is vital to create an attractive course and market to consumers. The success of the enterprise often depends on having staff who can be flexible, who take pride in recognizing what needs to be done, and who do it without being told. One of the big challenges in business is to find personnel who interact well together and who can adapt to meet the needs of each day effectively.

1. Gordon, Deborah, "Group-level dynamics in harvester ants: Young colonies and the role of patrolling," Animal Behavior, 1987, 35:833-843.
2. Gordon, Deborah, "Caste and change in social insects," in Oxford Surveys in Evolutionary Biology, Harvey and Partridge (Eds.), Oxford University Press, 1989, 6:56-72.
3. Gordon, D., Goodwin, B, and Trainor, L. "What is the function of encounter patterns in ant colonies?" Animal Behavior, 1993, 45:1083-1100.