Oxitec insects contain a genetic modification that causes their offspring to die, but the Oxitec insects can live and reproduce normally when they are fed a diet containing an antidote.
Oxitec males are released to mate with wild female pest insects; their offspring inherit the self-limiting gene and do not survive to adulthood. Releases of Oxitec males in large enough numbers over a sufficient time will suppress, or even eliminate, the target pest population.
Oxitec strains have no offspring unless supplied with the antidote; both male and female offspring die. Strains can be designed to die at different life stages. Released Oxitec insects and all of their offspring die within a few weeks so releases must be sustained to maintain the control. Where a male-only release is required, the sexes must be separated mechanically, which is possible in only a few insect species. Self-limiting genes are included in Oxitec’s products.
Female-specific Oxitec strains target the female offspring to ensure they don’t survive to adulthood unless supplied with the antidote. The sexes can be separated easily by excluding the antidote from the diet of the final, pre-release generation so that only males are produced for release. This offers a simpler way of separating males and females for release. Oxitec males are released to mate with pest females. Their female offspring do not survive and the population is suppressed. The female-specific self-limiting effect means that after a few generations the gene disappears from the population unless continued releases occur. Female-specific Oxitec genes are included in Oxitec’s public health and agricultural pest control products.