On
the other hand, the identical or reverse changes
in different organic contents during A stage reveal
their proportional importance for mineralisation.
As expected, both chitin and calcium carbonate are the most representative compounds in
the construction of the cuticle layers in S. serrata
throughout the molt cycle. The mirror images
with GAG peak and chitin depression in the
cuticle at A stage indicate that the GAG increase
represents an initial mineral nucleation period. In
S. serrata the organic fraction of new cuticle
forms from the D2 stage while mineralisation
occurs primarily during ecdysis.