December 1, 2025, 1:25 p.mDecember 1, 2025, 1:25 p.m
Violet light causes a ring of stem cells to grow on the outer edge of bristleworm eyes. As a result, their visual organs become larger throughout their lives, report the Viennese biologists Florian Raible and Kristin Tessmar-Raible and their teams.
The eyes of the bristleworm continue to develop through light. image: imago
The worms’ eyes can not only perceive light, but their development is also regulated by it, they explain. The study was published in the journal “Nature Communications”.
A light sensor makes this possible, the researchers from the Institute of Neuroscience and Developmental Biology at the University of Vienna as well as the Alfred Wegener Institute in Bremerhaven and the University of Oldenburg (both in Germany) found out. It is called “c-opsin” and occurs not only in the bristleworms examined (Platynereis dumerilii), but also in the retina of humans and other vertebrates. With a sufficient amount of light, it ensures that the nerve stem cells in the worm’s eyes multiply.
Bristleworm and fish eyes grow throughout life
“We found these dividing cells at the edge of the worm’s retina,” says Nadja Milivojev: “This is exactly the place where some vertebrates have their retinal stem cells for lifelong eye growth.” “These include amphibians such as salamanders, reptiles such as crocodiles, and many fish,” explained Florian Raible to the Austrian news agency APA: “In adult mammals such as humans, the eye usually no longer grows.”
A bearded firebristleworm underwater.Image: imago
The worms’ eyes have a similar structure to those of vertebrates, says Kristin Tessmar-Raible: “But they definitely evolved independently of each other, just like the eyes of molluscs like the octopus.” All of them use a lens to create a sharp image on the retina. “This is the same functional principle as a camera,” explains the researcher. The difference is that there is no retina with nerve cells that perceive light, but rather digital image sensors. (sda/apa)