Figure 1.

(a) The study area in northern Peru. Localities in yellow (San Roque, Shilcayo, Urauasha, El Tunel and Shapaja) are in the Andean cordillera, the orange locality (Pongo) is in the Amazon basin and the red localities (Shapajilla and Antena-Pongo) fall in the transition zone between the two areas. (b) Morphs used in the study and names of the localities where they were placed. The sets of morphs are sorted according to the phenotypic distance calculated under UV-vision between the heterozygote (Het.) and the local dominant morph (Hom. 1), from more similar (blue side of the arrow) to less similar (green side of the arrow).