Queen of Bees

Jennifer Fewell has spent her whole career studying bees and ants. But when she put a group of normally solitary ant queens together in the same colony, what she saw was a surprise even to her.

“Normally, these ants have to do everything for themselves out in nature. I watched as they spontaneously divvied up tasks in the lab—even more than queens that were used to working together,” the ASU biologist says.

At the time, division of labor in insects was nothing new. Years earlier, scientists had noticed that individual ant workers acted as experts at particular tasks in their complex colonies. However, most scientists thought that each ant’s expertise was primarily coded in its genes—that an ant is born to specialize in one task.

Fewell’s results showed something new. The solitary queens, which were never experts in the wild, would become specialists spontaneously in the laboratory. Not only that, but later results showed that the same ant would choose a different task depending on what others did.

Recognizing this anomaly, Fewell began an intensive study of the division of labor in ants and bees. ASU biologist Rob Page joined the study. Together, the researchers began testing a new model that explains why individuals do different jobs at even the most basic levels of social organization.

“This model is very simplistic,” Fewell explains. “It just says that individuals have a threshold—a point at which they’ll respond to a stimulus for a task by performing the task.”

This type of division of labor occurs everywhere. Fewell says that it even shows up in your house. Somebody washes the dishes and somebody vacuums the living room. Someone else takes out the trash.

According to Fewell, the model explains how jobs get divvied up without anyone being in charge. For example, if one roommate hates dirty dishes, he is likely to do the dishes before they pile up in the sink. If another roommate hates a dirty carpet, she will vacuum before her roommates even notice the dirt. According to Fewell’s model, ants, and maybe even people, have breaking points—thresholds that, once crossed, demand that they take action.

Fewell is now testing the “threshold model” with experiments on many different species of social insects.

In one experiment, she uses the model to predict how particular bees will interact in controlled situations. Fewell places two normally solitary queen bees together in an artificial hive. Like other solitary insects, they spontaneously divided labor based on their different tolerance thresholds. One spent more time guarding the nest while the other spent more time tunneling and excavating.

However, another factor also affected the bees’ behavior. The size of the tunnels in the hive proved to be a new variable. When both bees needed to pass through the same thin tunnel, the normally independent bees had a big decision to make.

In order to pass by one another to the different rooms, each bee had to expose its underside, which could allow the other bee an opportunity to sting it. So moving around wasn’t always easy.

Fewell combined the two factors into a single model of the bees’ behavior. She enlisted the expertise of mathematical modeler Raphael Jeanson. Together, they used complex systems modeling to create a computer model that represented the actions of the bees almost perfectly.

Fewell’s colleagues at ASU’s new Center for Social Dynamics and Complexity hope that a similar approach will allow them to do the impossible. They want to precisely predict the outcomes of social interactions before the experiment even starts.

“The eventual plan is to put all this into one big model that can tell us what’s going to happen,” Fewell adds. “It’s probably a long way off, but the implications are huge.”—Taylor Jackson