The structure and formation of the cuticulin layer in the epicuticle of an insect, Calpodes ethlius (Lepidoptera, Hesperiidae)
Version of Record online: 6 FEB 2005
Copyright © 1966 Wiley-Liss, Inc.
Journal of Morphology
Volume 118, Issue 4, pages 461–494, April 1966
How to Cite
Locke, M. (1966), The structure and formation of the cuticulin layer in the epicuticle of an insect, Calpodes ethlius (Lepidoptera, Hesperiidae). J. Morphol., 118: 461–494. doi: 10.1002/jmor.1051180403
- Issue online: 6 FEB 2005
- Version of Record online: 6 FEB 2005
The cuticulin layer is defined as the dense lamina (120–175 Å thick in Calpodes larvae, depending upon the stage) forming the outer part of the epicuticle in insects. It completely invests an insect except for the gut and the openings of some sense organs. It is the first layer to be secreted during the formation of new cuticle. The formation of the cuticulin membrane may be a useful model for studying the origin of membranes in general. It arises as a triple layer de novo and is not a modified plasma membrane. Growth is by accretion at the edges of patches of cuticulin which increase in area until they cover the new surface. The triple layer (i.e. three dense laminae) may develop striations about 30 Å apart transverse to the membrane, which perhaps form a sieve allowing small molecules to pass while protecting the cell from enzymes in the molting fluid. A similar porous structure persists in the tracheoles. After the resorption of molting fluid the triple layered structure again becomes obvious and the outermost layer separates from the other two to become what may be the surface lipid monolayer. The surface patterns in cuticle of various sorts probably arise by buckling of the cuticulin layer as it increases in surface area.