Uncovering the role of endocrine factors in decapod physiology

Crustaceans are a valuable food source and commercially important. In order to ensure population stability, environmental diversity and food security, understanding the underlying endocrinology of these arthropods is key. Dr Kenji Toyota, Marine Biological Station, Sado Island Center for Ecological Sustainability, Niigata University, is working on research to shed light on the mechanisms that control key stages in crustacean life cycles and better understand how they have adapted to the environment of Sado Island. The research involves field work, breeding-based experiments with high-performance liquid chromatography (HPLC) and next generation sequencing (NGS) to analyse endocrine factors and related genes, with a focus on the eyestalk-derived hormones found in decapod crustaceans. One of Toyota's key projects is focused on the environmental sex determination (ESD) and toxicogenomics of the water flea Daphnia. He and his collaborators have reported on how insect growth regulators (IGRs) have disrupted non-target arthropod species, which includes larval lethality, defects arising in the metamorphosis process and disruption in sexual differentiation. Toyota's work is highlighting the negative environmental impacts of waste products and chemicals and also uncovering knowledge that can assist in the management of populations in both wild and farmed settings. Toyota has revealed the endocrine mechanisms that control metamorphosis during larval development and uncovered the ecotoxicological impacts of IGRs. The researchers are also investigating the roles of hormones innate JH (methyl farnesoate) and ecdysteroids (20-hydroxyecdysone, 20E) in the progression of Kuruma prawns throughout the larval stages.