It’s fascinating to imagine how butterflies see their world

Common Bluebottles, an Australasia species of swallowtail butterfly, holds the record of the highest number of different vision cells within eyes in comparison to any other insect.

Researchers, who have been studying these big-eyed butterflies, have found that the species, Graphium sarpedon, possess around 15 classes of light-detecting vision cells, called photoreceptors. So far, no insect was known to have over nine.

Photoreceptors can be compared to the rods and cones present in the human eye. Common Bluebottles flaunt extraordinary big eyes and blue-green iridescent wings use visual communication, suggestive of the fact that they have unbelievable vision. Moreover, researchers haven’t expected that they would come across something like this.

Lead study author Kentaro Arikawa, a biology professor from the Graduate University for Advanced Studies in Japan, said, “We have studied color vision in many insects for many years, and we knew that the number of photoreceptors varies greatly from species to species,". "But this discovery of 15 classes in one eye was really stunning”.

Researchers described that the butterflies use all of their 15 photoreceptors simultaneously for sensing color, brightness, shape and movement. In comparison, humans have just four classes of photoreceptors, including three kinds of cones used for color vision and rods for distinguishing changes, shape, and movement in light and dark.

Arikawa added that butterflies probably have a slightly lower visual acuity as compared to ours; however, there are many other factors through which they enjoy an apparent advantage over us.

Butterflies have a quite huge visual field, better ability to pursue fast-moving objects and can even sense the difference between ultraviolet and polarized light. Arikawa mentioned that the way butterflies see their world seems fascinating.