Most insects have evolved to see the blue, green, and even ultraviolet spectrums. But most insects have trouble parsing one hue in particular: red. Even bees and other pollinators that visit traditionally vibrant poppies aren’t attracted by the visible coloration, but by the UV light reflected from their petals. Now, an international zoology team has discovered that some insect species can manage to see what their relatives cannot. According to a study published in the Journal of Experimental Biology, at least two beetle species living in the eastern Mediterranean environments can actually see red.
“To our knowledge, we are the first to have experimentally demonstrated that beetles can actually perceive the color red,” said Johnnes Spaethe, paper co-author and chair of zoology at Germany’s University of Würzburg.
Both Pygopleurus chrysonotus and Pygopleurus syriacus are small, fuzzy beetles that belong to the Glaphyridae family, and mostly feed on pollen from red flowering plants like buttercups, anemones, and poppies. This led researchers to wonder how they developed their preferences.
The team utilized a number of methods to determine the two beetles weren’t traveling to the red flowers simply due to a UV sensory situation similar to bees. After using a combination of color trapping, behavioral experiments, and electrophysiology, Spaethe and colleagues clearly showed each species includes four types of photoreceptors in their retinas. Aside from UV light, the bugs are able to process blues, greens, and deep reds—although field observations indicated the insects used true color vision to identify and visit red flowers.
“The prevailing opinion in science is that flower colors have adapted to the visual systems of pollinators over the course of evolution,” explained Spaethe.
The team’s latest findings may complicate this theory, however. In addition to Pygopleurus, two other genera in the larger beetle family (Eulasia and Glaphyrus) display widely different color preferences including red, white, violet, and yellow. This suggests the ability to see red—as well as nature’s many other colors—may be relatively more malleable than previously thought.
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