Fig. 11

A proposed schematic model for the involvement of specific proteins during eggshell formation and melanization in Aedes aegypti mosquitoes. A A primary follicle in the ovariole reaches maturity and an extracellular eggshell matrix forms between the oocyte and follicular epithelial cells around 48 h PBM. Enzymes involved in eggshell melanization and cross-linking are present but inactive during this stage. B As primary follicles initiate migration into an inner oviduct, the surrounding follicular epithelium sheds with the secondary follicle and germarium in the ovariole. The enzymes involved in eggshell melanization and cross-linking are still in their inactive forms within the inner, lateral, and common oviducts. C Once the eggs are deposited onto an oviposition substrate, eggs briefly uptake surrounding water and activate the melanization and cross-linking enzymes through the activity of Nudel and/or CATL3 leading to tanning and completion of the eggshell