Access

You are not currently logged in.

Access your personal account or get JSTOR access through your library or other institution:

login

Log in to your personal account or through your institution.

Spatial Variation in Phenotypic Selection on Floral Characteristics in an Epiphytic Orchid

Sol Taína Cintrón-Berdecía and Raymond L. Tremblay
Folia Geobotanica
Vol. 41, No. 1, Ecology and Population Dynamics of Terrestrial Orchids (Mar., 2006), pp. 33-46
Published by: Springer
Stable URL: http://www.jstor.org/stable/25134138
Page Count: 14
  • Download ($43.95)
  • Cite this Item
Spatial Variation in Phenotypic Selection on Floral Characteristics in an Epiphytic Orchid
Preview not available

Abstract

Spatial variation in twelve floral characters was examined in an epiphytic orchid Lepanthes rupestris to evaluate the strength and direction of phenotypic selection in seven riparian populations along two river basins in the Caribbean National Forest "El Yunque" for a range of 18-34 months. We evaluated selection on floral characters based on male (pollinaria removal) and female fitness (fruit set). Simple linear and quadratic regressions were used to evaluate the strength of directional, disruptive and stabilizing selections. Univariate and multivariate analyses were used to estimate the total strength of the selection acting on a character. Phenotypic selection was inconsistent among characters and populations. Few of the characters appeared to be under selection and none of them was found to be consistent throughout all populations. Inconsistency in selection coefficients among populations could suggest that selection is spatially variable. We only noted one character (column length) which had some consistency in differential selection coefficients among populations. Previous studies have shown that effective population sizes in L. rupestris are small and the observed "fitness differences" among populations could as easily be explained as stochastic events at play. We argue that the observed "fitness differences" in most characters and inconsistency among populations are likely from stochastic noise and not phenotypic selection. Consequently, we propose that random selection on character state support the hypothesis of genetic drift in small orchid populations.

Page Thumbnails

  • Thumbnail: Page 
[33]
    [33]
  • Thumbnail: Page 
34
    34
  • Thumbnail: Page 
35
    35
  • Thumbnail: Page 
36
    36
  • Thumbnail: Page 
37
    37
  • Thumbnail: Page 
38
    38
  • Thumbnail: Page 
39
    39
  • Thumbnail: Page 
40
    40
  • Thumbnail: Page 
41
    41
  • Thumbnail: Page 
42
    42
  • Thumbnail: Page 
43
    43
  • Thumbnail: Page 
44
    44
  • Thumbnail: Page 
45
    45
  • Thumbnail: Page 
46
    46