Cardenolide storage inDanaus chrysippus(L.) with additional notes onD. plexippus(L.)

Abstract

Danaus chrysippus was reared in the laboratory from stock obtained from Kampala (Uganda), Nairobi (Kenya), Dar-es-Salaam (Tanzania) and Freetown (Sierra Leone) and wild-caught samples from Nigeria, southwest Africa and Tanzania were also analysed. D. plexippus was reared on the same plants for comparison. It was found that the adult D. chrysippus is a poor and inconsistent storer of cardiac glycosides compared with D. plexippus , and contained, chiefly, highly polar cardenolides. Populations in East Africa are, on the whole, more efficient storers than those from West Africa, a factor which may contribute to the dearth of mimics in West Africa. Furthermore there appears to be a genetic element in the storage capacity of these butterflies, not merely a ‘mirror’ effect, depending on the cardenolide content of their food plants. Differences in storage capacity were shown between morphs alcippus from both Sierra Leone and Dar-es-Salaam and aegyptius from Tanzania and Dar-es-Salaam, reared side by side on the same tested food plants. In both cases aegyptius was the better storer but in other broods from Kenya, reared on Asclepias rich in cardenolides, this morph was negative for these substances. During the investigation strains of Asclepias curassavica were found which contained calotropin, but lacked calactin. D. plexippus reared on these plants also lacked calactin, but sequestered and stored it when fed on Gomphocarpus fruticosus which contained both substances. The methods for analysing cardenolides of this type are described. Maps are presented showing the distribution of the three principal morphs of D. chrysippus and the form albinus in Africa.

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

“…The question thus arises as to how the polymorphism originated and how it is maintained in an unpalatable species (Rothschild et al, 1975) (Smith, 1980;Smith et al, 1988). D. chrysippus is a savanna butterfly and its present wide distribution in Africa must be a relatively recent phenomenon associated with a decrease in the area covered by forest as a result of a drier climate, accelerated by an unprecedented impoverishment of forest vegetation from human activities, especially in the last few hundred years.…”

“…Maps showing the distribution of the forms of D. chrysippus in Africa are given in Owen & Chanter (1968), Owen (1971), Rothschild et al (1975) and Pierre (1973Pierre ( , 1980. 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.…”

Chemical Ecology of Poisonous Butterflies: Model or Mimic? A Paradox of Sexual Dimorphisms in Müllerian Mimicry

“…Similar to the American Danaus spp., the Old World milkweed butterfly, Danaus chrysippus (so-called plain tiger, widely distributed from Africa to tropical Asia) is assumed to be "poisonous" with its conspicuous appearance with a black apex and white subapical spots on the forewing in blight tawny-orange background coloration, likely as a typical model for various mimicry species (Smith 1973 larval stage. However, they are known to be poor and inconsistent sequesterers of CGs (Schneider et al 1975;Rothschild et al 1975;Mebs et al 2005). In order to confirm the toxicity of a local population of D. chrysippus in Okinawa, we examined CG contents in their body tissue.…”

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

“…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. to DASS) and supports numerous mimics (Smith, 1973a(Smith, , 1976(Smith, , 1979Owen and Smith, 1993;Owen et al, 1994).…”