Mandible of a copepod
Top: Image of the Chewing Surface
Bottom: False Color Image Depicting the Content ; Green, Silica; Orange-red, Chitin Blue, Resilin
Image: Michels et al.*
Copepods are small crustaceans that can be found in both oceans and freshwater. They feed on tiny animicules and phytoplankton including diatoms. Diatoms are protected from predators by a silica coating that is resistant to mastication. Copepods are able to crack open diatoms and release the nutrients. Copepods have a region of the mandibles adapted to processing diatoms and other food, the gnathobase. A group of scientists* have investigated the structure of the mandibles of the antarctic copepod, Rhincalanus gigas
in detail and found that the regions of the mandibles vary in properties. The cutting surface had high proportions of silica, surrounded by areas containing high proportions of resilin and chitin.
The silica in the cutting surface was found to be crystalline (alpha-cristobalite) and doped with aluminum. The combination of silica crystals and aluminum make a sharp,hard chewing surface capable of masticating diatoms. The area between the cutting “teeth” contains the flexible and compressible protein resilin. The resilin possibly cushions the impact when mandibles contact the food or each other. The resilin could also allow slight movement that facilitates mastication. The chitin is thought to provide a scaffolding for the depositing the silica.
Insects have similarly complex mouthparts. Studying these structures in Artropods can inform engineering of nano fabricated materials with similar function
*Michels, J., et al. New insights into the complex architecture of siliceous copepod teeth. Zoology (2015)
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