Ecological, behavioral, and genetic factors influencing the recombinant control of invasive pests

Invasive species are a major threat to biodiversity, cost the world economy billions of dollars annually, and are often difficult, if not impossible, to control using current approaches. Recombinant technologies could revolutionize management of such pests but would be subject to a range of genetic, behavioral, and ecological factors that could limit their efficacy or applicability. We use a realistically parameterized combined population dynamics/genetics model to assess the potential of, and constraints on, a suite of recombinant approaches that have been suggested for pest control. We show that, of the options suggested to date, a genetic construct that distorts operational sex ratios by sterilizing, killing, or sex-changing one gender and being inherited through the other, is not only potentially the most effective means of pest control, but also one that remains effective over the widest range of ecological and behavioral conditions. All methods, however, are sensitive in particular to the degree of density dependence in the pest population and to operational issues such as maximum copy number and stocking levels, which affect introgression rates. Optimal investment strategies for an integrated pest management program that includes the nonlinear interactions of recombinant strategies and complementary management options can be assessed through the sensitivity analyses. The subtle effects of even minor variability in some parameters, such as extra mortality due to the presence of the construct, further suggest that genetic techniques be applied in an active adaptive management framework, so that strategies can be regularly optimized as the impacts of a release program are assessed.