It's known that scallops have dozens, sometimes hundreds, of eyes. In fact, their retinal design provides an elegant example of nature's engineering. However, these structures are difficult to study in a lab due to drying and other physical deterioration.
So, Lia Addadi at the Weizmann Institute of Science and her team, including Benjamin Palmer and Gavin Taylor decided to try a cryo-scanning electron microscope and the rapid freezing of samples to keep delicate and important structures intact.
With this method, they discovered that scallops' eyes each have a segmented mirror that grows individually. They are made of square, flat, guanine crystals (a millionth of a meter wide) that link together into a grid.
Stacked groups of grids (20-30) have liquid filling the spaces between them. The crystals and separating spaces are 74 and 86 billionths of a meter thick which works well at reflecting blue-green light in the ocean environment.
The group also noticed that the mirror crystal segments are not inactive, but seem to grow inside the cells of the scallop’s eye, filling them up. Then, they join together to form a uniform mosaic layer.
So now that we know how scallops' eyes develop, the next research question is whether they all provide images individually or combine information into a single complex image? I can't wait to find out. Go science!
