Resistance evolution is a central obstacle to malaria control, whether in the parasite targeted by drugs or the mosquito targeted by insecticides. I will present two complementary lines of work that illustrate how evolutionary and ecological dynamics shape resistance outcomes. In mosquitoes, we used genetic crosses to track resistance alleles under different exposure regimes. Our results show that whether resistance spreads depends not only on the insecticide but also on dose, coverage, and inheritance patterns. Building on this, we evaluated four management strategies and found that “high-dose refuge” designs most effectively slowed resistance while preserving population control. On the parasite side, we examined competition between malaria strains. When strains shared the same environment, we observed strong competitive suppression; yet even when physically separated by a membrane, strains still influenced each other’s growth, sometimes negatively, sometimes positively. These hidden interactions suggest opportunities to harness ecological dynamics to constrain resistance. Together, these studies reveal how selective pressures and competitive interactions shape the trajectories of both parasites and vectors, and point toward resistance management strategies that may be able to exploit the principles of evolution.
