Nectar reward and advertisement in hummingbird-pollinated Silene virginica (Caryophyllaceae).

Published

Journal Article

We tested for an association between nectar and various floral traits and investigated their roles as primary and secondary pollinator attractants in hummingbird-pollinated Silene virginica. Our goal was to gain insight into the mechanisms of pollinator-mediated selection that underlies floral trait divergence within the genus. In a field population of S. virginica, we measured five floral and eight vegetative traits and quantified nectar volume, nectar sugar concentration, and total sugar reward (nectar volume × nectar sugar concentration). All three components of nectar reward were positively correlated to flower size, and nectar volume varied significantly among individuals within the population. To ascertain whether the correlation of specific floral traits with nectar reward influences the behavior of the primary pollinator of S. virginica, the ruby-throated hummingbird, Archilochus colubris, we investigated whether A. colubris preferred the expression of floral traits associated with high nectar volume and total sugar reward. We accomplished this by constructing floral arrays consisting of artificial flowers that had equal nectar quantity and total sugar reward but that differed in petal area and corolla tube diameter, which were positively correlated with nectar quantity and total sugar reward in our field study. In observations of visitation frequencies to the various floral-trait combinations, hummingbirds preferentially visited artificial floral phenotypes with larger petal displays, with the greatest preference for floral phenotypes with both larger petals and wider corolla-tube diameters. This association between primary and secondary floral attractants and hummingbird discrimination of floral features supports the concept that the floral traits of S. virginica reflect pollinator-mediated selection by the principal pollinator.

Full Text

Duke Authors

Cited Authors

  • Fenster, CB; Cheely, G; Dudash, MR; Reynolds, RJ

Published Date

  • December 2006

Published In

Volume / Issue

  • 93 / 12

Start / End Page

  • 1800 - 1807

PubMed ID

  • 21642126

Pubmed Central ID

  • 21642126

International Standard Serial Number (ISSN)

  • 0002-9122

Digital Object Identifier (DOI)

  • 10.3732/ajb.93.12.1800

Language

  • eng

Conference Location

  • United States