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.

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.

New Slants on Ornament Asymmetry

Matthew R. Evans and B.J. Hatchwell
Proceedings: Biological Sciences
Vol. 251, No. 1332 (Mar. 22, 1993), pp. 171-177
Published by: Royal Society
Stable URL: http://www.jstor.org/stable/49847
Page Count: 7
  • Read Online (Free)
  • 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.
New Slants on Ornament Asymmetry
Preview not available

Abstract

Elaborate sexual ornaments are found in many species, and some of them have been shown to have important functional roles. What limits the development of such ornaments? The fluctuating asymmetry hypothesis proposes that high-quality individuals will produce large symmetrical ornaments, the converse being true for low-quality individuals. Negative relations between ornament size and asymmetry have been demonstrated and have been taken as supporting evidence for this hypothesis. Asymmetry in the tail ornament of male scarlet-tufted malachite sunbirds (Nectarinia johnstoni) was investigated. During this process we discovered various problems in the theory and methods of analysis; we illustrate some of these using the sunbird data. We show that, because there are various ways of presenting the data, it is impossible to fail to obtain relations between asymmetry and some measures of trait size. This illustrates the problem that there is no clear null hypothesis for these analyses, and we discuss various possibilities. Fluctuating asymmetry theory cannot necessarily be applied to traits which are composed of more than one unit, and we discuss why similar trends have been found in these multi-component traits and single-unit traits. It is possible that aerodynamic and mechanical constraints may force symmetry on larger ornaments; this may also explain why similar trends have sometimes been found in the ornaments of the two sexes. We conclude that this hypothesis may not provide an adequate explanation for the honesty of ornamentation.

Page Thumbnails

  • Thumbnail: Page 
171
    171
  • Thumbnail: Page 
172
    172
  • Thumbnail: Page 
173
    173
  • Thumbnail: Page 
174
    174
  • Thumbnail: Page 
175
    175
  • Thumbnail: Page 
176
    176
  • Thumbnail: Page 
177
    177