Genetics of a Difference in the Male Genitalia of East and West African Stocks of Papilio dardanus (Lep.)

Abstract

THE famous African butterfly Papilio dardanus Brown is highly polymorphic in the female, while the males are monomorphic and non-mimetic¹. The species has been divided taxonomically into a number of sub-species, mainly on the basis of quantitative variation in wing pattern of the males^2–4. Several of these races are isolated from all others on islands and mountainous areas. However, five named races are not geographically isolated from their neighbours and the male wing pattern, since it tends to show a clinal distribution, is unsatisfactory for delimiting their exact distributions. The western race (dardanus) might be thought to be more distinct than the others, because of the morphology of the male genitalia⁴. In the eastern races there is a long spine on the inner surface of the valve; the western race usually has no spine (Fig. 1). In a narrow zone north of Lake Victoria where the races meet, both types are found, together with intermediates with very short spines, which in west Africa are known only as rarities.