Ant foraging diversity: a simple and elegant explanation
Science can be creative and elegant.
To illustrate this fact, I want to bring to your attention a groundbreaking review paper that was recently published in Myrmecological News, written by Michele Lanan of the University of Arizona.
Usually the terms “groundbreaking” and “review paper” aren’t paired with one another. Review papers usually codify existing ideas, propose some new ones that may fall flat. And, if you chat with an editor, you’ll learn that good reviews really improve a journal’s impact factor.
Then there’s this amazing review I loved so much I had to write this post about it. Even if you don’t know a thing about ants, I’m betting you’ll love how the paper draws a clear and simple explanation from complex interacting phenomena.
Ant people are asked about foraging behavior quite often. How and why do ants make trails? Why do some species make trails and others don’t? Until now, our answers were vaguely correct but relied heavily on generalizations. Now, after Michele Lanan scoured pretty much every paper that’s ever collected data on foraging behavior and ecology, we have a quantitative and robust explanation that is powerfully simple and elegant.
We’ve known that foraging behaviors are structured by that ways in which food is available. Among all ants, there’s a huge variety of foraging patterns. Some are opportunistic hunter-gatherers, others are nomadic raiders, and some use trunk trails, as in the figure below. These patterns reflect differences in food availability.
Figure from M. Lanan 2014, Myrm News 20:50-73.
How, exactly, is it that the properties of food availability can predict how ants forage? In an analytically robust and predictable manner, that works for all ants throughout the phylogeny? It doesn’t require an n-dimensional hyperspace to understand foraging patterns of ants. It only needs a 4-dimensional space.
Figure from M. Lanan 2014, Myrm News 20:50-73.
Lanan took into account four properties of food items: size, spatial distribution, frequency of occurrence, and depletability. She arranged these variables along four axes (as on the right), and showed how this this 4-dimenstional space foraging patterns in the figure above.
How do these foraging patterns distribute across the major ant subfamilies? Are some lineages more variable than others, and what might account for these differences? What other beautiful figures and photographs are in the review that illustrate the relationship between spatiovariability of food and foraging biology? As they say on Reading Rainbow, you’ll have to read the review to find out!
As a disclaimer, I should mention that the author of this paper is a collaborator and friend of mine. And she is leading The Ants of the Southwest short course this summer which I’m also teaching — and spaces are still available!
But that’s not why I’m featuring this paper. I am enthusiastic about this paper because it so obviously resulted from a labor of love for the ants, and is a culmination of years of reflection. This is just a downright gorgeous piece of science, and the more people that see it — and the more recognition that the author gets — the better.