Department of Geology & Geophysics, Yale University, New Haven, CT 06520-8109, USA.
J Insect Sci. 2011;11:66. doi: 10.1673/031.011.6601.
Members of the diverse butterfly families Nymphalidae (brush-footed butterflies) and Riodinidae (metalmarks) have reduced first thoracic limbs and only use two pairs of legs for walking. In order to address questions about the detailed morphology and evolutionary origins of these reduced limbs, the three thoracic limbs of 13 species of butterflies representing all six butterfly families were examined and measured, and ancestral limb sizes were reconstructed for males and females separately. Differences in limb size across butterflies involve changes in limb segment size rather than number of limb segments. Reduction of the first limb in both nymphalids and riodinids appears particularly extensive in the femur, but the evolution of these reduced limbs is suggested to be a convergent evolutionary event. Possible developmental differences as well as ecological factors driving the evolution of reduced limbs are discussed.
蝴蝶科的不同家族（鳞翅目）和凤蝶科（金属斑蝶）的成员的第一胸肢都有所缩小，仅用两对腿来行走。为了研究这些缩小的肢体的详细形态和进化起源，对代表所有六个蝴蝶科的 13 种蝴蝶的三个胸肢进行了检查和测量，并分别对雄性和雌性的祖先肢体大小进行了重建。蝴蝶的肢体大小差异涉及肢体节段大小的变化，而不是肢体节段数量的变化。在鳞翅目和凤蝶科中，第一肢的缩小尤其在股骨中表现得特别广泛，但这些缩小的肢体的进化似乎是一个趋同进化事件。讨论了可能的发育差异以及驱动缩小肢体进化的生态因素。
