Different species may independently arrive at the same biological solution. This is a phenomenon known as parallel evolution. Researchers at Osaka Metropolitan University (OMU) have discovered that dragonflies detect red light in a way that is very similar to how mammals, including humans, do. This discovery could have implications far beyond insect biology, as many medical techniques rely on red light.
Human vision relies on eye proteins called opsins. These proteins allow us to recognize different colors. We have three main types, each tuned to blue, green, or red wavelengths, which when combined provide full-color vision.
Dragonflies are unique among insects for their ability to detect red light. A research team led by Professor Mitsumasa Koyanagi and Professor Akihisa Terakita of the OMU Graduate School of Science has identified a specific opsin in dragonflies that responds to light around 720 nm. This wavelength is beyond the deepest red that humans can normally see.
“This is one of the most red-sensitive visual pigments ever discovered,” Terakita said. “Dragonflies are probably able to see red light more deeply than most insects.”
Why deep red vision is important to dragonflies
Scientists have proposed that this increased sensitivity helps dragonflies find mates. To explore this idea, they looked at reflectance, which refers to how much light a surface reflects. In the case of dragonflies, reflected light plays an important role in how individuals see each other.
The results of the measurements revealed that there are clear differences between males and females in the way they reflect light from red to near-infrared. This suggests that males may rely on these subtle visual cues to quickly identify females during flight.
An amazing example of parallel evolution
“Surprisingly, the mechanism by which dragonfly red opsin senses red light is identical to that of red opsin in mammals, including humans. This is an unexpected result and suggests that the same evolutionary process occurred independently in distantly related lineages,” said first author Ryu Sato, a graduate student.
Insects and mammals are very distant relatives, but both seem to have arrived at the same molecular strategy for sensing red light.
medical engineering dragonfly vision
The research team also uncovered important details that could make this discovery useful for technology and medicine. They identified a single location within the opsin protein that determines how the protein responds to light. By changing this position, they were able to shift the protein’s sensitivity further toward longer wavelengths, closer to the infrared range.
They then engineered a version of the protein that responds to even longer wavelengths and demonstrated that cells containing this modified opsin could be activated by near-infrared light.
Potential applications in optogenetics
This research is believed to be particularly valuable in optogenetics, a field that uses light-sensitive proteins to control and study cells within living tissues. Longer wavelength light can penetrate deeper into the body, so having proteins that respond to near-infrared light could allow researchers to reach cells that are otherwise difficult to access.
“In this study, we succeeded in shifting the sensitivity of the modified near-infrared opsin of the Odonata family to longer wavelengths, and confirmed that the modified near-infrared opsin can induce cellular responses in response to near-infrared light,” Professor Koyanagi said. “These findings demonstrate that this opsin is a promising optogenetic tool that can detect light even deep within organisms.”
This research Cell and molecular life science.
