A refined roadmap to decapod sexual manipulation

Many decapod crustaceans with sexual dimorphism in body size are economically significant species for fisheries and aquaculture, making monosex culture a desirable practice to increase farmers' yield and profits. It is well established that the male-specific androgenic gland (AG) mediates masculinization in decapods by producing and secreting the insulin-like AG hormone (IAG). However, IAG is not a sex-determining factor; hence, iag silencing in decapods does not always lead to successful sex change. Since the establishment of monosex populations in the giant freshwater prawn Macrobrachium rosenbergii, the same AG/iag manipulation approach has been attempted in economically significant penaeid shrimps, crabs, crayfish and spiny lobsters, to no avail. There are many factors at play with species-specific intricacies which require close examination when addressing monosex production. This review provides a refined roadmap to successful sexual manipulation in decapod crustaceans, highlighting the key caveats to be considered and critical gaps in knowledge such as the timing of iag expression compared to the development of sexual characteristics, the relationship between iag and a master regulator, as well as silencing capacity. Lastly, this review examines what the future might hold for monosex aquaculture in decapods, taking into consideration novel technologies such as gene editing.