Butterflies have played an important role in our understanding of evolutionary biology since the field’s inception. Butterflies are one of the most vivid examples of adaptive colouration including sexual selection, crypsis (camouflage) and mimicry.
Explaining the phenomena of mimicry and polymorphism, described by H W Bates and F Muller, was one of the first real tests faced by Darwin and Wallace's theory of evolution.
One species central to these discussions, following its initial study by Roland Trimen in the 1860’s, was the African Mocker Swallowtail, or Flying Handkerchief, Papilio dardanus. This species is a polymorphic Batesian mimic, with its females belonging to at least 6 mimicry rings among African butterflies.
Prior to the groundbreaking work of Roland Trimen, only males of P. dardanus were known from most of mainland Africa, and the 'species' such as P. hippocoon and P. trophonius were only known from female specimens. At the time of their description, this was not unusual, given the scarcity of material from Africa, and the inequalities in sex ratios typical among collected butterflies. However, Roland Trimen and his collaborators realised that these could all be males and females of a single species. This theory was proved correct when P. dardanus was bred in captivity: when butterflies reared from a single batch of eggs would produce male butterflies like P. dardanus and females identical to those of ‘P. hippocoon’ or ‘P. trophonius.'. The name Papilio dardanus, being older, was the correct species name and the names hippocoon, trophonius etc. are now used to refer to colour morphs of the mimetic females.