Macrobrachium prawns are voracious predators of the freshwater snails that host the flatworms responsible for bilharzia (schistosomiasis), a health burden in many African countries. A novel strategy to decrease the disease in Africa involves the use of prawns as biocontrol agents of the snails. Although the endemic African river prawn Macrobrachium vollenhovenii is a natural candidate for aquaculture and biocontrol, efforts to domesticate it have been unsuccessful to date, and it is not

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... e in the large quantities required for aquaculture and biocontrol. The Asian giant prawn Macrobrachium rosenbergii has been cultured worldwide for decades. Recently, novel biotechnologies were developed to create monosex (all-male) non-breeding populations for aquaculture that we suggest are also ideal for biocontrol in Africa. Since the above 2 prawn species are of the same genus, exhibit similar sizes and require a female pre-mating molt prior to egg fertilization, the potential for cross-breeding between the 2 species must be tested. To assure that all-male populations of M. rosenbergii will not pose such an ecological threat, we carried out cross-breeding experiments with M. vollenhovenii. Both interspecies encounters and attempts at artificial insemination revealed that fertilization does not occur between the 2 species. Our results demonstrate both behavioral and physiological pre-zygotic reproductive barriers between these species. We suggest that all-male M. rosenbergii can be used as an aquaculture species and as a biocontrol agent in areas where M. vollenhovenii occurs without concern for hybridization.