title: Pollinator shifts as triggers of speciation in painted petal irises (Lapeirousia: Iridaceae).
abstract: OBJECTIVE
  Adaptation to different pollinators has been hypothesized as one of the main factors promoting the formation of new species in the Cape region of South Africa. Other researchers favour alternative causes such as shifts in edaphic preferences. Using a phylogenetic framework and taking into consideration the biogeographical scenario explaining the distribution of the group as well as the distribution of pollinators, this study compares pollination strategies with substrate adaptations to develop hypotheses of the primary factors leading to speciation in Lapeirousia (Iridaceae), a genus of corm-bearing geophytes well represented in the Cape and presenting an important diversity of pollination syndromes and edaphic preferences.
  
  
  METHODS
  Phylogenetic relationships are reconstructed within Lapeirousia using nuclear and plastid DNA sequence data. State-of-the-art methods in biogeography, divergence time estimation, character optimization and diversification rate assessments are used to examine the evolution of pollination syndromes and substrate shifts in the history of the group. Based on the phylogenetic results, ecological factors are compared for nine sister species pairs in Lapeirousia.
  
  
  RESULTS
  Seventeen pollinator shifts and ten changes in substrate types were inferred during the evolution of the genus Lapeirousia. Of the nine species pairs examined, all show divergence in pollination syndromes, while only four pairs present different substrate types.
  
  
  CONCLUSIONS
  The available evidence points to a predominant influence of pollinator shifts over substrate types on the speciation process within Lapeirousia, contrary to previous studies that favoured a more important role for edaphic factors in these processes. This work also highlights the importance of biogeographical patterns in the study of pollination syndromes.
authors: Jodrell Laboratory, Royal Botanic Gardens, Kew, Richmond, Surrey TW9 3DS, UK.
authors: Félix
authors: F
authors: Forest
authors: Peter
authors: P
authors: Goldblatt
authors: John C
authors: JC
authors: Manning
authors: David
authors: D
authors: Baker
authors: Jonathan F
authors: JF
authors: Colville
authors: Dion S
authors: DS
authors: Devey
authors: Sarah
authors: S
authors: Jose
authors: Maria
authors: M
authors: Kaye
authors: Sven
authors: S
authors: Buerki
mesh_terms: D000818:Animals; D001499:Bayes Theorem; D018744:DNA, Plant / Q000235:genetics; D035264:Flowers / Q000502:physiology*; D049810:Genetic Speciation; D027621:Iridaceae / Q000502:physiology*; D016013:Likelihood Functions; D010802:Phylogeny; D058974:Phylogeography; D054817:Pollination / Q000502:physiology*; D013019:South Africa; D013045:Species Specificity
chemical_list: D018744:DNA, Plant
keywords: Biogeography; Iridaceae; Lapeirousia; diversification; edaphic factors; phylogenetics; pollinator; shift; speciation