Contrasting phylogenetic signals and evolutionary rates in floral traits of Neotropical lianas

• Published in: Biological journal of the Linnean Society Vol. 102; no. 2; pp. 378 - 390
• Main Authors: ALCANTARA, SUZANA, LOHMANN, LÚCIA G
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.02.2011; Wiley-Blackwell
• Subjects: ancestral character states; Bignoniaceae; Biological and medical sciences; Biological evolution; calyx; corolla; Evolution; Fundamental and applied biological sciences. Psychology; Genetics of eukaryotes. Biological and molecular evolution; gynoecium; K-statistic; lianas; morphological evolution; natural selection; Pagel's ancestral character state reconstruction; phylogenetically independent contrasts; phylogeny; pollen; pollinators; quantitative traits; tropics; Reconstruction; quantitative traits; Flower; Statistical analysis; Pagel's ancestral character state reconstruction; Biological evolution; Tropical zone; morphological evolution; Phylogeny; ancestral character states; Statistics; phylogenetically independent contrasts; Signal; K-statistic; Dicotyledones; Morphology; Angiospermae; Liana; Spermatophyta; Bignoniaceae; Neotropical Region
• ISSN: 0024-4066; 1095-8312
• DOI: 10.1111/j.1095-8312.2010.01567.x

The diversity of floral forms has long been considered a prime example of radiation through natural selection. However, little is still known about the evolution of floral traits, a critical piece of evidence for the understanding of the processes that may have driven flower evolution. We studied the pattern of evolution of quantitative floral traits in a group of Neotropical lianas (Bignonieae, Bignoniaceae) and used a time-calibrated phylogeny as basis to: (1) test for phylogenetic signal in 16 continuous floral traits; (2) evaluate the rate of evolution in those traits; and (3) reconstruct the ancestral state of the individual traits. Variation in floral traits among extant species of Bignonieae was highly explained by their phylogenetic history. However, opposite signals were found in floral traits associated with the attraction of pollinators (calyx and corolla) and pollen transfer (androecium and gynoecium), suggesting a differential role of selection in different floral whorls. Phylogenetic independent contrasts indicate that traits evolved at different rates, whereas ancestral character state reconstructions indicate that the ancestral size of most flower traits was larger than the mean observed sizes of the same traits in extant species. The implications of these patterns for the reproductive biology of Bignonieae are discussed. © 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2011, 102, 378-390.