Keeping an eye on coloration: ecological correlates of the evolution of pitcher traits in the genus Nepenthes (Caryophyllales)

Nepenthes is a genus of carnivorous pitcher plants with high intra- and interspecific morphological diversity. Many species produce dimorphic pitchers, and the relative production rate of the two morphs varies interspecifically. Despite their likely ecological importance to the plants, little is known about the selective context under which various pitcher traits have evolved. This is especially true of color-related traits, which have not been examined in a phylogenetic context. Using field observations of one polymorphic species (N. gracilis) and phylogenetic comparative analysis of 85 species across the genus, we investigate correlations between color polymorphism and ecological factors including altitude, light environment, and herbivory. In N. gracilis, color does not correlate to amount of prey-capture, but red pitchers experience less herbivory. Throughout the genus, color polymorphism with redder lower pitchers appears to be evolutionarily favored. We found a lack of phylogeneti...

猪笼草属（Nepenthes）是一类食虫猪笼草，具有极高的种内和种间形态多样性。该属许多物种可产生二型猪笼草，且两种形态的相对产生率存在种间差异。尽管这些性状对植物可能具有重要生态意义，但人们对各类猪笼草性状演化的选择背景知之甚少。这一点在颜色相关性状上尤为明显——此类性状尚未在系统发育背景下得到研究。通过对一种多态物种（纤细猪笼草，N. gracilis）的野外观察，以及对全属85个物种的系统发育比较分析，我们探究了颜色多态性与海拔、光照环境及食草作用等生态因子之间的相关性。在纤细猪笼草中，颜色与猎物捕获量无相关性，但红色猪笼草遭受的食草作用更少。在整个猪笼草属中，具有颜色更红的下位猪笼草的颜色多态性似乎在进化上更受青睐。我们发现缺乏系统发育...