ASCB 2015—Ants Self-Organize, Just like Cells in Nervous Systems and Embryos, Says Deborah Gordon

Deborah Gordon, Professor of Biology at Stanford University, will speak at ASCB 2015 on Sunday, December 13, about “The Ecology of Collective Behavior.”

Stanford biologist Deborah M. Gordon has spent much of the last 30 years studying the self-organization of ant colonies. Forget about queens ruling their colonies. With ants, organization is all a matter of who you bump into, what signals you pick up, and where you are at the moment. All these countless individual interactions accumulate into the colony’s collective decision-making, apportioning resources, responding to threats and opportunities, and starting new colonies, all without top down management. This classic unit-by-unit, moment-by-moment, from-the-bottom-up self-organization should be familiar to cell biologists, according to Gordon. It’s what drives many emergent biological systems—cells into tissue, neurons into nervous systems, and zygotes into embryos.

Which explains why Gordon, who has a PhD in zoology, but is not anything like a traditional entomologist, will be speaking at ASCB 2015 in the Sunday, December 13, morning symposium, “Wisdom of Crowds: Collective Decision-Making by Cells and Organisms.” Her talk is called, “The Ecology of Collective Behavior.”

As a model for emergent organization, ants have much in common with cells, Gordon explained in a recent interview. Take neurons, she said. Her lab uses a concept borrowed from neural system development to understand how an ant “counts” interactions. “How does an ant know the rate at which it meets other ants?” Gordon said. “We were thinking about that by analogy with a neuron. A neuron adds up its stimuli; from other neurons. It’s a process called a leaky integrator because each electrical impulse that a neuron receives has some decay because some charge leaked out. What happens in a neuron is that it responds to successive stimuli, if the next one happens before the previous one has decayed, then enough charge has accumulated and a neuron will fire.”

Gordon continued, “We’re thinking an ant assesses its rate of interaction in a similar way. It has a neurophysiological response with each interaction, which has some decay. If it has enough of them often enough, the ant is likely to do something like go out and forage. We’re using models from theoretical neuroscience to see from our data how an ant assesses its recent rate of interaction.”

Gordon’s lab is on the Stanford campus but she does her ant fieldwork in Arizona, for a very practical reason. “I chose to study ants in the desert because the ants are large and dark against a light bare background, and so very easy to see,” Gordon said. But how Gordon came to study ants isn’t quite as simple. When she was deciding on an area of research to pursue in the late 1970s, Gordon recalled, “I was interested in developmental biology because I was interested [in processes] that work without central control. I was looking for a system where I could study collective behavior where I could see everything, so I came to ants in a very abstract way.” Gordon added, “[Ants] make it possible to see the interactions that create collective behavior, you can watch it as it’s happening. Now it’s possible to watch an embryo as it’s happening, but back then you had to kill it and slice it, and let another one grow a little bit more… Ants, you can keep watching.”

Even after more than 30 years of watching ants, Gordon doesn’t regret her choice of subject. “What keeps surprising me is how such a messy noisy process can create such predictable results. The [individual] ants themselves don’t seem to respond to things in a very clear or deterministic way, but ant colonies respond very predictably,” Gordon said.

The insights that ants have given Gordon into how individual noise accumulates into collective behavior are germane, she believes, to the understanding of other biological processes. In cell differentiation, cell-cell signaling, mechanical transduction, and chemical gradients would seem to create howling confusion and yet cells—and ants—usually make predictable collective decisions. “I think that we may able to see in ants as a model system how variability in the way that ants respond to interactions leads to variation in the way colonies are regulated, and maybe that can give us clues on the effects of variation in other systems like neural systems,” she said.
ASCB 2015 will be Gordon’s first time at a large cell biology meeting. She was pleased to be invited to speak but confesses to an ulterior motive. “I’m hoping for more collaborations with cell biologists. That’s really why I’m looking forward to this meeting.”