Bauder J A-S, Warren A D, Krenn H W
Department of Integrative Zoology, University of Vienna, Althanstraße 14, A-1090 Vienna, Austria.
McGuire Center for Lepidoptera and Biodiversity, Florida Museum of Natural History, University of Florida, Gainesville, U.S.A.
J Res Lepid. 2014 Dec 1;47:65-71.
Exaggerated morphologies have evolved in insects as adaptations to nectar feeding by natural selection. For example, the suctorial mouthparts of butterflies enable these insects to gain access to floral nectar concealed inside deep floral tubes. Proboscis length in Lepidoptera is known to scale with body size, but whether extreme absolute proboscis lengths of nectar feeding butterflies result from a proportional or disproportional increase with body size that differs between phylogenetic lineages remains unknown. We surveyed the range of variation that occurs in scaling relationships between proboscis length and body size against a phylogenetic background among Costa Rican Hesperiidae. We obtained a new record holder for the longest proboscis in butterflies and showed that extremely long proboscides evolved at least three times independently within Neotropical Hesperiidae. We conclude that the evolution of extremely long proboscides results from allometric scaling with body size, as demonstrated in hawk moths. We hypothesize that constraints on the evolution of increasingly long butterfly proboscides may come from (1) the underlying scaling relationships, i.e., relative proboscis length, combined with the butterfly's flight style and flower-visiting behaviour and/or (2) developmental constraints during the pupal phase. Lastly, we discuss why butterflies did not evolve similar scaling relationships as hawk moths.
在昆虫中，夸张的形态特征已经通过自然选择进化成为对吸食花蜜的适应性特征。例如，蝴蝶的吸管式口器使这些昆虫能够获取隐藏在深花管内的花蜜。已知鳞翅目昆虫的喙长与体型成正比，但吸食花蜜的蝴蝶的绝对喙长极端值是由与体型成比例还是不成比例的增加导致的，以及这种情况在不同系统发育谱系之间是否存在差异，目前尚不清楚。我们在哥斯达黎加弄蝶科的系统发育背景下，调查了喙长与体型之间的比例关系的变化范围。我们获得了蝴蝶最长喙的新纪录保持者，并表明极长的喙在新热带区弄蝶科中至少独立进化了三次。我们得出结论，极长喙的进化是由与体型的异速生长比例关系导致的，就像天蛾那样。我们假设，蝴蝶喙越来越长的进化可能受到以下因素的限制：(1) 潜在的比例关系，即相对喙长，以及蝴蝶的飞行方式和访花行为，和/或 (2) 蛹期的发育限制。最后，我们讨论了为什么蝴蝶没有进化出与天蛾类似的比例关系。
