Most complex colour vision in an insect

According to research published in the journal Frontiers in Ecology and Evolution on 8 March 2016, the common bluebottle butterfly (Graphium sarpedon) – native to the Indian subcontinent, south-east Asia, Japan and eastern Australia – has 15 types of colour receptors in its eyes, sensitive to ultraviolet and human-visible light. This is compared to only one photoreceptor in the eyes of seals, two in cats, dogs and horses, three in humans and four in most birds. This results from a combination of five visual pigments and various types of filters. The dorsal and ventral half of a common bluebottle's eyes see the world in different colours.

The 15 receptors break down as follows: ultraviolet (UV); violet (V); blue (B: with three subclasses); blue-green (BG), green (G: with four subclasses); and red (R: with five subclasses).

This study was a collaboration between The Graduate University for Advanced Studies (Japan) and the National Taiwan University (Chinese Taipei).

Until this research, the golden birdwing butterfly (Troides aeacus) of south-east Asia held the record for most complex colour vision among insects, with nine different colour receptors in its eyes.

The only animals known to surpass this level of complexity in terms of their colour vision are stomatopods, aka mantis shrimps, which have up to 16 colour receptors in their eyes.