Figure 1. Distribution of the sister-species M. helenor and M. achilles across South America.

The gray area represents the whole distribution of M. helenor, and the dotted area indicates the localities where M. helenor is in sympatry with M. achilles. Note that the different subspecies of M. helenor are found in different localities and display substantial variations in the proportion of black vs. blue areas on the dorsal sides of their wings. For example, M. h. bristowi and M. h. theodorus are allopatric in Ecuador, with their respective distribution separated by the Andes such that they are never in contact. While M. h. bristowi is found on the Pacific side of the country and has a wide blue band on the dorsal side of its wings, M. h. theodorus is found in Western Amazonia and displays a narrow blue band on the dorsal side of its wings. However, M. helenor is sympatric with M. achilles throughout the Amazonian rainforest. In French Guiana, the subspecies M. helenor helenor and M. achilles achilles display convergent dorsal color patterns with thin blue bands (Llaurens et al., 2021).