Data from: 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 phylogenetic signal for most traits, either suggesting that most
traits are labile or reflecting the uncertainty regarding the underlying
tree topology. This work highlights ecological correlates of the vast
phenotypic diversity of this group of tropical plants. We point to a need
for future work examining herbivores of Nepenthes and experimental
investigations on color polymorphism.