Methyl farnesoate inhibition of late stage ovarian development and fecundity reduction in the black tiger prawn, Penaeus monodon

There is mounting evidence that the terpenoid hormone methyl farnesoate (MF) plays important roles in regulating reproductive processes in crustaceans. To gain further information on its roles and possible modes of action, MF was orally administered to ablated Penaeus monodon at a concentration of 5.5 μg per gram of diet, and a range of reproductive performance criteria measured. Results confirmed that MF plays a role in the reproductive process of this species. Specifically, under the conditions of this study, MF inhibited late stage ovary development and reduced fecundity in ablated prawns. The impact of the artificial diet (without additional MF) relative to a squid-mussel diet, was also assessed in this study and although it increased the quality of larvae produced, it also increased inhibition of late stage ovary development. Thus while the current study has increased our knowledge of MF by isolating an ovary developmental stage at which MF regulates reproduction in P. monodon, factors that determine the extent of its effect and whether it has a stimulatory or inhibitory effect, remain unknown. Until these factors are identified, the application of MF as a means of predictably manipulating egg production in captive prawns remains problematic.