División de Colecciones Zoológicas, Instituto de Ecología y Sistemática, Carr de Varona, Capdevila, Boyeros, AP 8029, CP 10800 Ciudad de la Habana, Cuba.
Biol Lett. 2011 Jun 23;7(3):414-8. doi: 10.1098/rsbl.2010.0844. Epub 2010 Nov 3.
Four phylogenetically independent lineages of frogs are currently known to sequester lipid-soluble skin alkaloids for which a dietary source has been demonstrated. We report here a remarkable fifth such instance, in Eleutherodactylus iberia and Eleutherodactylus orientalis, two species of miniaturized frogs of the family Eleutherodactylidae from Cuba. Six pumiliotoxins and two indolizidines were found in E. iberia, one of the smallest frogs in the world and characterized by a contrasting colour pattern for which we hypothesize an aposematic function. Analyses of stomach content indicated a numerical prevalence of mites with an important proportion of oribatids-a group of arthropods known to contain one of the pumiliotoxins detected in E. iberia. This suggests that miniaturization and specialization to small prey may have favoured the acquisition of dietary skin alkaloids in these amphibians.
目前已知有四种与进化无关的青蛙谱系会隔离脂溶性皮肤生物碱，并且已经证明了这些生物碱的饮食来源。我们在这里报告了一个显著的第五个例子，即来自古巴的 Eleutherodactylidae 科的微型青蛙 Eleutherodactylus iberia 和 Eleutherodactylus orientalis。在 E. iberia 中发现了六种 pumiliotoxins 和两种 indolizidines，它是世界上最小的青蛙之一，其颜色图案形成鲜明对比，我们假设其具有警示功能。对胃内容物的分析表明，螨虫的数量普遍存在，其中重要的比例是属于节肢动物的食菌螨目，该目已知含有在 E. iberia 中检测到的 pumiliotoxins 之一。这表明，在这些两栖动物中，体型缩小和专门以小型猎物为食可能有利于获取饮食中的皮肤生物碱。
