Tunable Structural Colors in Fish and Copepods

David Wang Auditorium, 3rd floor Dalia Maydan Bldg.
Dr. Dvir Gur

Dr. Dvir Gur

Dept. of Physics of Complex Systems and the Dept. Molecular Cell Biology, Weizmann Institute of Science.234 Herzl Street, Rehovot 7610001 Israel. dvirgur@gmail.com

Some of the most striking and vivid colors in nature are produced from guanine-based structural colors. Such systems are widespread and can be found in many organisms across different phyla including fish, spiders, lizards, and crustaceans1. Some of these organisms have the amazing ability to change their color in response to external stimuli. The copepods are small planktonic shrimps that reflect brilliant and vivid colors. We have discovered that the males can change their colors2, identified the color change mechanism, and showed that this change is entirely reversible2,3. Fish are utilizing guanine-based reflectors in both their eyes and skin to reflect light. Using synchrotron-based micro X-ray diffraction, together with cryo-electron microscopy and optical analyses, we have demonstrated that color change in fish is due to tilting of intercellular guanine crystals4 and that the complex optical response of the fish iris is facilitated by the development a high-order organization of multilayered guanine-based crystal reflectors and pigments.


1. Gur, D., Palmer, B., Weiner, S., and Addadi, L. (2017). Light Manipulation by Guanine Crystals in Organisms: Biogenic Scatterers, Mirrors, Multilayer Reflectors and Photonic Crystals. Adv.Func. Mat.

2. Gur, D., Leshem, B., Farstey, V., Oron, D., Weiner, S., and Addadi, L. (2016). Light-induced color change in the sapphirinid copepods: tunable photonic crystals. Adv.Func. Mat. 26.(9), 1393-1399.

3. Gur, D., Leshem, B., Pierantoni, M., Farstey, V., Oron, D., Weiner, S., and Addadi, L. (2015). Structural Basis for the Brilliant Colors of the Sapphirinid Copepods. J. Am. Chem. Soc. 137, 8408-8411.

4. Gur, D., Palmer, B.A., Leshem, B., Oron, D., Fratzl, P., Weiner, S., and Addadi, L. (2015). The Mechanism of Color Change in the Neon Tetra Fish: a Light-Induced Tunable Photonic Crystal Array. Angew. Chem. Int. Edit. 54, 12426-12430.

Host: Prof. Boaz Pokroy