Species complexes are common, especially among insect disease vectors, and understanding how barriers to gene flow among these populations become established or violated is critical for implementation of vector-targeting disease control. Anopheles gambiae, the primary vector of human malaria in sub-Saharan Africa, exists as a series of ecologically specialized populations that are phylogenetically nested within a species complex. These populations exhibit varying degrees of reproductive isolation, sometimes recognized as distinct subspecies. We have sequenced 32 complete genomes from field-captured individuals of Anopheles gambiae, Anopheles gambiae M form (recently named A. coluzzii), sister species A. arabiensis, and the recently discovered “GOUNDRY” subgroup of A. gambiae that is highly susceptible to Plasmodium. Amidst a backdrop of strong …