Natural selection on floral volatile production in Penstemon digitalis: highlighting the role of linalool

Plant Signal Behav. 2013 Jan;8(1):e22704. doi: 10.4161/psb.22704. Epub 2012 Dec 6.


Natural selection is thought to have shaped the evolution of floral scent; however, unlike other floral characters, we have a rudimentary knowledge of how phenotypic selection acts on scent. We found that floral scent was under stronger selection than corolla traits such as flower size and flower color in weakly scented Penstemon digitalis. Our results suggest that to understand evolution in floral phenotypes, including scent in floral selection, studies are crucial. For P. digitalis, linalool was the direct target of selection in the scent bouquet. Therefore, we determined the enantiomeric configuration of linalool because interacting insects may perceive the enantiomers differentially. We found that P. digitalis produces only (S)-(+)-linalool and, more interestingly, it is also taken up into the nectar. Because the nectar is scented and flavored with (S)-(+)-linalool, it may be an important cue for pollinators visiting P. digitalis flowers.

Keywords: Penstemon digitalis; corolla color; floral scent; flower size; linalool; phenotypic selection; pollination.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acyclic Monoterpenes
  • Biological Evolution*
  • Flowers / metabolism*
  • Monoterpenes / metabolism*
  • Odorants*
  • Penstemon / genetics*
  • Penstemon / metabolism
  • Phenotype
  • Plant Nectar / metabolism
  • Pollination*
  • Selection, Genetic*
  • Stereoisomerism
  • Volatile Organic Compounds / metabolism


  • Acyclic Monoterpenes
  • Monoterpenes
  • Plant Nectar
  • Volatile Organic Compounds
  • linalool