Sexual dimorphism of mud crab, genus Scylla between sexes based on morphological and physiological characteristics

Sexual dimorphism in mud crab occurs from the early crablet stage until the crab has the ability to mate. The development of sexual dimorphism is involved in both morphology and physiology. In terms of morphology, the mud crab expressed several characteristics such as the abdomen, chelae, size, weight and reproductive system (gonopore, gonopod and gonad). Regulation of the morphology changes interacts with the physiological process of several hormonal signals such as androgenic gland hormone, crustacean female sex hormone, gonadotropins, methyl farnesoate, neurotransmitters and steroids. The sexual dimorphism of economic importance can be observed on male commercial value, which is demonstrated in chelae enlargement, higher weight and rapid growth. Meanwhile, the female crabs offer the pleasant flavour of egg masses (ovary) that render the high economic value. These criteria urge the farmers to enhance the profitability through monosex culture, which involves establishing several types of sex manipulation technology (interspecific hybridization, temperature manipulation, hormonal therapy and androgenic gland manipulation). The fundamental knowledge of sexual dimorphism is importantly necessary to the application of sex manipulation technology, which may become the potential solution to optimize the production of crab domestication.