Researchers have uncovered a new understanding of how foraging ants find food by leaving pheromone trails that connect their colony to various food sources when many are available. This significant finding has led to the development of the first model that explains how ants create these trails in response to multiple food locations.
It’s a common sight — ants marching in an orderly line over and around obstacles from their nest to a food source, guided by scent trails left by scouts marking the find. But what happens when those scouts find a comestible motherlode?
A team from Florida State University, led by Assistant Professor of Mathematics Bhargav Karamched, has made an important discovery regarding how foraging ants seek food. They leave pheromone trails that connect their colony to multiple food sources when they are available. This work has resulted in the creation of a pioneering model that explains the formation of trails to several food sources.
Karamched, who is also part of FSU’s Institute of Molecular Biophysics, along with music arts administration graduate student Sean Hartman, published their findings in “Walk This Way: Modeling Foraging Ant Dynamics in Multiple Food Source Environments” in the Journal of Mathematical Biology in September.
“The strength of mathematics lies in its ability to produce models that replicate data observed in experiments and make reliable predictions about future behavior,” Karamched stated. “One of our key discoveries is that when an ant has access to various food sources, it will start by forming multiple trails to each of them.”
Using mathematical modeling, analysis, and computer simulations, Karamched studies challenges in neuroscience and cell biology. Hartman, who completed dual bachelor’s degrees in Mathematics and Music from FSU in May 2023, is expected to finish his graduate studies this spring. He approached Karamched to participate in a Directed Individual Study (DIS), which allows FSU Honors Program students to engage in hands-on, one-on-one research experiences with faculty mentors, providing Hartman with a chance to delve deeper into mathematical modeling.
“I have always been passionate about mathematics and wanted to explore research opportunities in it,” Hartman explained. “Dr. Karamched’s research on ant trails captivated me, prompting my interest in further investigating and modeling this compelling subject.”
Foraging is crucial for an ant colony’s survival, with ants organizing their activities using pheromones. When an ant discovers food, it releases a chemical trail to guide others to the find. Through computational simulations and stochastic modeling, the team found that ants tend to travel to the food source nearest their nest when multiple sources exist.
“In our study, we categorized the ants into two groups: foragers and returners,” Karamched said. “Foragers roam in search of food, whereas returners head straight back to the nest after locating food, making their movement more predictable. This allows for accurate predictions of their behavior and destinations.”
The research team, which includes collaborator Shawn Ryan, an associate professor in the Mathematics and Statistics Department at Cleveland State University, examined how the concentration of pheromones influences ant behavior. The probability of their models relied on the dynamics of these chemical signals. Returner ants would release fewer pheromones based on how far the food was from the nest. Higher pheromone levels lead to a stronger scent trail, especially important for distant food sources.
“Once my code was fully verified and functioning correctly, the formation of multiple trails became clear and easy to comprehend,” Hartman remarked. “It was exciting to see how equal distance food sources could sustain multiple trail paths in equilibrium. However, if one food source was even slightly closer to the nest, the ants would eventually consolidate into a single trail leading to that source. At that moment, it felt like all of our efforts had finally come to fruition.”
The model presented in this research is designed to be straightforward and applicable to other organisms and biological systems that use pheromones for communication. This includes various bacteria, slime molds, insects, fish, some reptiles, and mammals.
“The basis for studying this collective behavior begins with analyzing the fundamental pheromone concentration gradient,” Karamched explained. “This chemical signaling enables organisms to coordinate activities over large distances, which is an intriguing process, whether at the microscopic level or with more complex species.”
