Polymorphism of the tropical butterfly, Danaus chrysippus L., in Africa

Abstract

SUMMARYThe polymorphism of Danaus chrysippus is anomalous since it is a distasteful butterfly. In a field study of the B locus polymorphism in Ghana, significant changes in the morph frequencies were recorded over eighteen months at Cape Coast. There were also significant differences between localities. There was some evidence that brown morphs are favoured by wet conditions, and that orange forms have higher survival rates as caterpillars. There were no differences between forms in larval foodplants, sex ratio, body size, wing damage, mating success, or in the effects of weather on adult activity. There was however, strong assortative mating between forms. Crosses with Kenyan females gave aberrant segregations for the sex chromosomes and the C locus. The results are discussed with regard to the hypothesis that polymorphism arose as a result of the overlapping of previously isolated geographical races.

Genetics of the mimetic African butterfly Hypolimnas misippus: hindwing polymorphism

“…In (Clarke, Sheppard and Smith, 1973;Gordon, 1984;Smith, Shoesmith and Smith, 1988) There is a melanic specimen (blw/5M), almost certainly a heterozygote (A-/Bb/M--/--or A'" -M-/--), in the Nairobi Museum, caught in 1939 at Katera in Uganda, where alcippus is probably not uncommon (Owen and Chanter, 1968 the Bulawayo Museum has a melanie specimen (brw/5PvJ), the only wild melanie immima-alcippoides (Aa/Bb/mm---or A'"a/mm/--) recorded, caught in Bulawayo in 1979. The East and Central African melanism records suggest a widespread distribution for the melanism gene although it is rare everywhere.…”

Incomplete sexual isolation in sympatry between subspecies of the butterfly Danaus chrysippus (L.) and the creation of a hybrid zone

“…The formal colour genetics of D. chrysippus ( Figure 2) is fairly well known (Owen and Chanter, 1968;Clarke et al, 1973;Smith 1975aSmith , 1980Smith , 1998Gordon, 1984;Smith et al, 1998). Hindwing colour and pattern are controlled by the autosomal A locus: 2a and 2c have the genotype AA, whereas 2b and 2d are aa.…”

“…While the partial vicariance of the three subspecies probably reflects past geographical isolation, in Uganda, southern Kenya, Tanzania and parts of several neighbouring countries, but rarely elsewhere, two or more interbreeding polymorphic forms, that match in phenotype their respective subspecies and share their names, are found in sympatry and hybridise (Owen and Chanter, 1968;Smith, 1975aSmith, , 1980Gordon, 1984). The polymorphism is unique among the 157 species of the subfamily Danainae (Ackery and Vane-Wright, 1984); it is, moreover, a surprising feature in an aposematic species that is chemically defended (Rothschild et al, 1975;Brower et al, 1975Brower et al, , 1978Brown, 1984; JA Edgar in litt.…”

Polymorphism and evolution in the butterfly Danaus chrysippus (L.) (Lepidoptera: Danainae)

“…As it is both a Batesian model for several unrelated species, belonging to four different butterfly families (or subfamilies depending on the authority) and also a Müllerian mimic sharing in rings with several other unrelated unpalatable species, it is a remarkable exception to the rule that both Batesian models and Müllerian mimics are monomorphic (Owen, 1971;Smith, 1980;Gordon, 1984). The polymorphism is best developed in East and Central Africa, especially in Uganda; there are also large areas, both within and outside Africa, where the butterfly is monomorphic and this is the general rule, with only local exceptions, throughout its extensive Palaearctic, Oriental and Australasian range.…”

“…The switch between orange and brown ground colour phenotypes (which have not received Latin names) probably has little impact on generalized mimetic resemblance (Gordon, 1984), especially as many of the mimics are similarly variable; Smith (1980) has suggested that the orange-brown polymorphism relates to climatic adaptation, possibly through thermoregulation, influencing activity levels and, in particular, courtship behaviour.…”