Tucson Standard

Colors play a crucial role in communication among animal species, serving various purposes such as attracting mates and warning predators. A new study conducted by researchers at the University of Arizona delves into the evolutionary history of color vision and its diverse functions in both animals and plants.

The research team, led by John J. Wiens from the Department of Ecology and Evolutionary Biology at the University of Arizona, discovered that color vision in animals evolved over 500 million years ago. This predates the emergence of colorful fruits by approximately 150 million years and colorful flowers by about 300 million years. The findings are detailed in a publication in Biological Reviews.

The study examines two primary types of color signals used by animals: warning signals and sexual signals. It also explores how plants utilize conspicuous colors for seed dispersal through fruits and pollen distribution via flowers.

"We wanted to know when bright coloration evolved and what was the purpose of that coloration. That's largely why we pursued this study," said Zachary Emberts, co-author of the study and assistant professor at Oklahoma State University.

Wiens noted that warning color signals appeared around 150 million years ago, while sexual color signals emerged roughly 100 million years ago. "There has been a dramatic explosion of both warning and sexual color signals in the last 100 million years," he stated.

Despite evolving much earlier, color vision's exact influence on this rapid development remains unclear. However, Wiens identified three key groups contributing to this surge: ray-finned fishes in marine environments, along with birds and lizards on land.

Warning signals are more prevalent than sexual ones because they do not require well-developed eyes or even color vision from their bearers to communicate danger effectively. In contrast, sexual signals necessitate advanced visual capabilities between males and females for successful communication using these cues.

"In the future, it would be even more interesting to study what drives the ability of animals to see specific colors like red or blue," Emberts added.

Zachary Emberts received support during much of this manuscript's preparation through a postdoctoral fellowship from the U.S. National Science Foundation (grant DBI-1907051).