Oriental Hornet (Vespa orientalis)
Photosynthesis is usually the province of the plants. Very few animals can actually make energy from sunlight. But, some few members of the animal kingdom have harnessed the sun by getting the necessary solar panels to “go green.”
An ancient process, photosynthesis began between 3.75 to 3 billion years ago in single-celled organisms likely related to cyanobacteria. This process uses the sun’s energy to convert carbon dioxide to compounds such as sugars that are capable of producing energy for the cell. As cells evolved and became more complex, these photon-loving bacteria (cells without a nucleus also called prokaryotes) were then incorporated into the evolving cells as plastids and used as energy sources. Eventually, these single-celled eukaryotes (cells with a nucleus that are more complex than prokaryotes) would radiate into plants and would rely on photosynthesis for billions of years. Animalia, however, has not pursued this path. Instead, the animal kingdom has used ATP to provide the necessary energy for life.
But, a few animals have re-established photosynthesis as an energy mechanism, indicating either that the potential for this system remained with the more complex animals, or more likely, that these animals developed this energy powerhouse on their own in a bizarre example of convergent evolution.
The oriental hornet (Vespa orientalis) has evolved yellow patches located on the dorsal surface of the abdomen that Plotkin et al (Plotkin M et al: Solar energy harvesting in the epicuticle of the oriental hornet (Vespa orientalis) Naturwissenschaften (2010) 97:1067–1076) have shown are photosynthetic or at least harvest light as an energy source. In a competitive world, the extra energy obtained from this photosynthetic patch creates a successful edge. As a bonus, it permits this wasp to be active during mid-day with the maximum output of photons when other wasps are not so active.
Extraocular photoreception is found in many if not most creatures, but perhaps this extra light is never used so prudently as it is in the oriental wasp.