Defensive role of leaf trichomes in resistance to herbivorous insects in Datura stramonium

Authors

  • P. L. Valverde,

    1. Departamento de Ecología Evolutiva, Instituto de Ecología, Universidad Nacional Autónoma de México, Apartado Postal 70–275, México 04510, Distrito Federal, Mexico
    2. Departamento de Biolo?a, Universidad Autónoma Metropolitana, Unidad Iztapalapa, Apartado Postal 55–535, México 09340, Distrito Federal, Mexico
    Search for more papers by this author
  • J. Fornoni,

    1. Departamento de Ecología Evolutiva, Instituto de Ecología, Universidad Nacional Autónoma de México, Apartado Postal 70–275, México 04510, Distrito Federal, Mexico
    Search for more papers by this author
  • J. NÚÑez-Farfán

    1. Departamento de Ecología Evolutiva, Instituto de Ecología, Universidad Nacional Autónoma de México, Apartado Postal 70–275, México 04510, Distrito Federal, Mexico
    2. Department of Ecology and Evolutionary Biology, University of Connecticut, Torrey Life Science Building, Storrs, CT, USA
    Search for more papers by this author

P. L. Valverde, Departamento de Biologia, Universidad Autónoma Metropolitana, Unidad Iztapalapa, Apartado Postal 55–535, México 09340, Distrito Federal, México. e-mail: plvp@xanum.uam.mx

Abstract

This study assessed the role of leaf trichome density as a component of resistance to herbivores, in six populations of Datura stramonium. Phenotypic selection on plant resistance was estimated for each population. A common garden experiment was carried out to determine if population differences in leaf trichome density are genetically based. Among population differences in leaf trichome density, relative resistance and fitness were found. Leaf trichome density was strongly positively correlated to resistance across populations. In 5 out of 6 populations, trichome density was related to resistance, and positive directional selection on resistance to herbivores was detected in three populations. Differences among populations in mean leaf trichome density in the common garden suggest genetic differentiation for this character in Datura stramonium. The results are considered in the light of the adaptive role of leaf trichomes as a component of defence to herbivores, and variable selection among populations.

Ancillary