Access

You are not currently logged in.

Access JSTOR through your library or other institution:

login

Log in through your institution.

If You Use a Screen Reader

This content is available through Read Online (Free) program, which relies on page scans. Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.
Journal Article

Examining Hypotheses Generated by Field Measures of Sexual Selection on Male Lizards, Uta palmeri

Diana K. Hews
Evolution
Vol. 44, No. 8 (Dec., 1990), pp. 1956-1966
DOI: 10.2307/2409606
Stable URL: http://www.jstor.org/stable/2409606
Page Count: 11
Were these topics helpful?
See something inaccurate? Let us know!

Select the topics that are inaccurate.

Cancel
  • Read Online (Free)
  • Download ($4.00)
  • Subscribe ($19.50)
  • Add to My Lists
  • Cite this Item
Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.
Examining Hypotheses Generated by Field Measures of Sexual Selection on Male Lizards, Uta palmeri
Preview not available

Abstract

I examined sexual selection in the iguanid lizard Uta palmeri by measuring phenotypic selection in a cohort of males. Relative fitness was estimated by copulation rate from one breeding season, and I analyzed selection on five morphological traits (snout-vent length, mass, jaw length, head width, and head depth) and on male territory quality. Only territory quality and head depth were identified as direct targets of selection in a linear selection gradient analysis. Head depth was suggested to also be subject to quadratic selection. All traits exhibited significant directional selection differentials, suggesting indirect selection also was present because of the correlation of these traits with direct targets of selection. I used these results to generate hypotheses about the mechanisms of selection. For traits not identified as direct targets of selection (snout-vent length, mass, head width, jaw length), I could accept the null hypothesis of no female preference for the analyzed male traits; if these morphological traits were preferred by females in mate choice, they would have been identified as direct targets of selection. Exploring possible functional relationships within the cohort, I found that all five morphological traits contributed to explaining variation in territorial status. And in staged aggressive interactions between males that were similar in snout-vent length and mass, winning was associated only with greater head depth and not with head width or jaw length. Several possible interpretations of these results are presented. This study suggests that differential mating success arising from variation in territory quality gives rise to indirect selection on morphology. The possible mechanisms giving rise to the proposed direct selection on head depth require further study.

Page Thumbnails

  • Thumbnail: Page 
1956
    1956
  • Thumbnail: Page 
1957
    1957
  • Thumbnail: Page 
1958
    1958
  • Thumbnail: Page 
1959
    1959
  • Thumbnail: Page 
1960
    1960
  • Thumbnail: Page 
1961
    1961
  • Thumbnail: Page 
1962
    1962
  • Thumbnail: Page 
1963
    1963
  • Thumbnail: Page 
1964
    1964
  • Thumbnail: Page 
1965
    1965
  • Thumbnail: Page 
1966
    1966