Department of Zoology, University of Florida, 32611, Gainesville, Florida.
J Chem Ecol. 1985 Jan;11(1):85-103. doi: 10.1007/BF00987608.
Florida queen butterflies are highly variable in cardenolide content and, in three populations studied, contained less cardenolide than did a sample of sympatric Florida monarchs. The possibility that queens stored a more potent set of cardenolides from their host plants (and therefore were as well protected as monarchs, even at lower concentrations) is refuted by Chromatographic analysis of wild butterflies, as well as controlled laboratory rearings. It therefore appears that, with respect to cardenolides, monarchs are better defended than are queens. Consequently, cardenolides are unlikely to explain the apparent shift in Florida viceroy mimicry away from resemblance of the monarch, toward mimicry of the queen. Other hypotheses to explain this mimetic phenomenon are suggested. Adult monarchs exhibit significant negative correlations between the concentration of cardenolide stored in their tissues and both body size and weight, whereas queens show no such correlations. The implications of these results for the study of "metabolic costs" of allelochemic storage are discussed. Chromatographic evidence is provided that monarchs do breed in south Florida during the winter months and that the likely host plant employed by the population studied wasAsclepias curassavica. This represents the first practical application of cardenolide "fingerprinting" to identify the larval host plants of wild danaid butterflies.
佛罗里达帝王蝶的强心甾内酯含量变化很大，在所研究的三个种群中，其强心甾内酯含量均低于同域分布的佛罗里达黑脉金斑蝶的含量。从野外蝴蝶的色谱分析以及控制实验室饲养来看，女王蝶从其寄主植物中储存了一套更有效的强心甾内酯（因此即使浓度较低，也能像黑脉金斑蝶一样受到很好的保护）这一可能性被否定了。因此，就强心甾内酯而言，黑脉金斑蝶比女王蝶受到更好的保护。因此，强心甾内酯不太可能解释佛罗里达副王蝶拟态从类似黑脉金斑蝶向类似女王蝶的明显转变。此外，还提出了其他解释这种拟态现象的假说。成年黑脉金斑蝶体内储存的强心甾内酯浓度与其体型和体重之间存在显著的负相关关系，而女王蝶则没有这种相关性。这些结果对研究化学防御的“代谢成本”具有重要意义。色谱证据表明，黑脉金斑蝶在佛罗里达州南部冬季繁殖，而所研究种群可能使用的寄主植物是垂序商陆。这是首次将强心甾内酯“指纹图谱”实际应用于鉴定野生的 Danaid 蝴蝶幼虫的寄主植物。
