The ornate boxfish boasts a striking array of hexagonal spots and sharp stripes that leave no room for a lack of detail. These intricate markings have captivated the attention of engineers at the University of Colorado Boulder, who found themselves pondering the origins of this distinct appearance.
Over 70 years ago, the brilliant mathematician Alan Turing, credited with inventing modern computing, proposed a theory regarding the formation of animal patterns. He suggested that chemical agents would diffuse through the skin tissue, akin to creamer dispersing in a cup of coffee. These chemicals would interact and inhibit one another, ultimately giving rise to diverse patterns. However, Turing’s theory failed to address the mystery of how these patterns could remain so precisely defined, particularly in a species like the ornate boxfish. The ornate boxfish
In a recent study published in the journal Science Advances, a team of engineers from the University of Colorado Boulder delved into the concept of diffusiophoresis as a potential mechanism for generating these sharp patterns. Diffusiophoresis refers to the movement of suspended molecules in a fluid in response to a concentration gradient of another chemical. This phenomenon causes small particles, in this case chromatophores (pigment cells), to gather and clump together, shedding light on the formation of these distinct patterns.
When the scientists computed Turing’s equation, modified to include this process, the simulations they generated showed the molecules’ path had always created sharp outlines, unlike the fuzzy, ill-defined spots that Turing’s theory alone would create.
“What we were kind of curious about really was that if it is diffusion, then the patterns should not be sharp … the colors should not be so striking,” said study coauthor Ankur Gupta, an assistant professor of chemical and biological engineering at the University of Colorado Boulder. “So, what gives that striking sharpness to these patterns? That’s where diffusiophoresis comes in.”