Observation of an anisotropic texture inside the wax layer of insect cuticle

Michel Mitov (1) , Vanessa Soldan (2) , Stéphanie Balor (2)

1 CEMES-NeO - Nano-Optique et Nanomatériaux pour l'optique
2 CBI - Centre de Biologie Intégrative

The outermost part of insect cuticles is very often covered with wax, which prevents desiccation and serves for chemical communication in many species. Earlier studies on cuticular waxes have mainly focused on their chemical composition revealing complex mixtures of lipids. In the absence of information on their physical organization, cuticular waxes have been considered isotropic. Here we report the presence of parallel stripes in the wax layer of the carapace of the scarab beetle, Chrysina gloriosa, with a textural periodicity of ca. 28 nm, as revealed by electron microscopy of transverse sections. Observations at oblique incidence argue for a layered organization of the wax, which might be related to a layer-by-layer deposition of excreted wax. Our findings may lay the foundation for further studies on the internal structure of cuticular waxes for other insects.

Mots clés: insect physiology; cuticle; wax; physical organization

Domaines: Zoologie des invertébrés; Morphogenèse

Michel Mitov, Vanessa Soldan, Stéphanie Balor. Observation of an anisotropic texture inside the wax layer of insect cuticle. Arthropod Structure and Development, 2018, 47 (6), pp.622-626. ⟨hal-01994861⟩