Why is South Africa so rich in butterfly species, and why are so many of them endemic?

South Africa has a higher level of biodiversity in the Papilionoidea (butterflies) than might be expected from its relatively high latitude. In order to understand this phenomenon we consider the impact of continental drift on oceanic circulation, topographic changes wrought by persistent uplift, climatic consequences such as periodic cooling and aridification, and the resultant vegetational changes in Africa since the late Cretaceous period. This narrative is compared with evidence from dated phylogenies of southern African butterfly groups, such as the highly speciose lycaenid genera Thestor, Chrysoritis and Lepidochrysops. Certain satyrine genera are also considered such as Bicyclus, all genera of the tribe Dirini, and Pseudonympha of the subtribe Ypthimina of tribe Satyrini.Particularly influential vegetation changes were the transitions from forest to grassland and savanna, and later to the karoo biomes and fynbos. This resulted in the plant heterogeneity seen today, and influenced the cladogenesis and speciation of the butterfly groups under review. Adaptations like the use of cold-adapted grasses as host plants in the Satyrinae and ant association (ultimately aphytophagy) in some aphnaeine and polyommatine lineages allowed such butterflies to occupy the large variety of ecological niches provided by the vegetational changes. This led to the current highly speciose and endemic characteristics of multiple South African butterfly genera.