A team of Australian scientists has unlocked the mystery of how bees can successfully identify colors across varying light conditions, and it involves three extra eyes on the top of their heads called ocelli. The function of these extra eyes has never been fully understood, but new research discovered each ocelli contains two upwards pointing color receptors that can accurately measure the color of ambient light. This allows bees to better identify the true color of an object and target their flower of choice across a variety of light conditions.
One of the researchers mapped the neural tracings from the ocelli and discovered that these receptors are connected to the parts of a bee's brain responsible for color perception. The only question remaining was how these two particular color receptors could allow the bees to interpret the entire color spectrum from red to ultraviolet?
The team built a mathematical model showing that if the ocelli focused on two specific wavelengths, ultraviolet and blue, they could cover most typical light levels a bee would encounter in their natural environment. This model accurately explains why bees cannot successfully interpret flower colors under yellow artificial light and also why bees with blocked ocelli generally forage only in the middle of the day when light conditions are constant.
This research offers a clever, and simple, solution to achieving color constancy across our camera, robotic and drone systems. By incorporating two small, skyward pointing sensors in a camera to register the color of the ambient light, the researchers suggest that an object's true color could be identified across most light conditions.
As well as having benefits for general photography, the technique could prove extremely useful in industrial applications, bringing improvements in machine vision that would sort colored objects, such as ripe fruits or mineral-rich sands, to be identified easily across a variety of complex illumination conditions.
"The strength of this study lies in the combination of modeling, behavioral analysis, and neuro-anatomy," says Professor Marcello Rosa, one of the authors of the study. "It shows how modern, interdisciplinary neuroscience can point to an elegant solution to classical problems in vision."
The team's study was published in the journal Proceedings of the National Academy of Sciences (PNAS).