In crustaceans, cathepsin A functioned in the innate immune system . The purified cathepsin A proteins of E. sinensis can effectively digest the spermatophore wall . Cathepsin B was reported to control the developmental processes in insects and other arthropods. Cathepsin D is necessary for the formation of the yolk. Cathepsin L regulates the development of the ovary in many species including L. vannamei. Cathepsins A, B, C, D, F, and L were found in AG transcriptome. Cathepsin A was significantly upregulated while cathepsin D was significantly downregulated in SP AG, implying that these two types of cathepsins may play essential roles in the spermatogenesis process.