Many of the most dangerous human diseases are transmitted by insect
vectors. After decades of repeated insecticide use, all of these vector
species have demonstrated the capacity to evolve resistance to
insecticides. Insecticide resistance is generally considered to
undermine control of vector-transmitted diseases because it increases
the number of vectors that survive the insecticide treatment. Disease
control failure, however, need not follow from vector control failure.
Here, we review evidence that insecticide resistance may have an impact
on the quality of vectors and, specifically, on three key determinants
of parasite transmission: vector longevity, competence, and behaviour.