The phrase “solar powered hornets” may conjure terrifying images of a futuristic, stinging swarm of eco-conscious, half-insect, half-machine hornets. But these hornets might already exist. And don’t worry, they’re just normal hornets.
Researchers have recently discovered that the Oriental hornet may be capable of harvesting energy from sunlight. The majority of wasps and hornets are most active in the early morning. But entomologists have long known that Oriental hornets get most of their work done in the middle of the day when the sun is brightest. Working on a hunch that the hornets may be able to derive energy from sunlight, researchers took a closer look at the hornet’s abdominal exoskeleton using an atomic force microscope. They found that the exoskeleton is made up of a microscopic structure of ridges. When sunlight hits these ridges it scatters across the surface, allowing the hornets to maximize the amount of sunlight they absorb.
Although most of the Oriental hornet’s exoskeleton is brown, a bright yellow band encircles its abdomen. The pigment responsible for this yellow coloration is called xanthopterin. Based on experiments with artificial xanthopterin solar cells, researchers have shown that the yellow pigment is capable of converting sunlight into electricity. Although the exact biological mechanism that Oriental hornets use to convert sunlight to energy is unknown, it seems likely that xanthopterin plays a role.
When we think about a living thing converting sunlight to energy we usually think of plants and photosynthesis, but this discovery challenges current ideas about how insect metabolism can work. A typical workday for Oriental hornet drones involves digging out and expanding their underground nests. The extra energy obtained from sunlight might be crucial for the hornets to complete this gruelling labor. Of course, the microscopic ridges on the hornets’ exoskeletons could have evolved for some purpose other than sunlight absorption, so additional research is needed to confirm whether the hornets are actually using xanthopterin to harvest energy from sunlight.
Plotkin, M., Hod, I., Zaban, A., Boden, S., Bagnall, D., Galushko, D., & Bergman, D. (2010). Solar energy harvesting in the epicuticle of the oriental hornet (Vespa orientalis) Naturwissenschaften, 97 (12), 1067-1076 DOI: 10.1007/s00114-010-0728-1
Thanks to my friend, Sean, for the heads up on this story.