Biotechnology, biocontrol and conservation: Potential approaches-harnessing RNAi-based sex-differentiation manipulations in decapods

Invasive species of various taxa, including crustaceans and snails, are harmful to freshwater ecosystems, inflicting a reduction in biodiversity, vast losses for agriculture, alterations in natural ecosystems, and even some human health issues (such as bilharzia). We describe here some destructive invasive species of crustaceans and snails that can be controlled using biotechnological solutions. Specifically, we propose the use of sexually manipulated non-breeding all-male decapod crustacean populations generated through novel techniques that use temporal gene silencing via RNA interference (RNAi), namely, non-genetically modified organisms (non GMO), to control invasive species. The first part of the chapter deals with the control of invasive and destructive freshwater snails using snail-eating freshwater prawns; specifically we propose the use of all-male prawn populations to act as non-invasive and sustainable biocontrol agents. Freshwater prawns have already been shown to act as voracious predators of a few freshwater snail species. Since male prawns grow faster, reach larger size and do not migrate like females, it is likely that they will act as efficient biocontrol agents over snails. The second part of the chapter deals with the proposed control of invasive crustaceans by skewing the sex ratio of the invasive populations by repetitive releases into the invasive populations of neo-females, which bear 100 % male progeny. Since RNAi is becoming widely used and since the commercial use of RNAi-based biotechnologies for the production of neo-females and all-male prawn populations has already been implemented, our proposed solution is readily available for eco-protection applications.