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.

Aggression, Density, and Sexual Dimorphism in Chernetid Pseudoscorpions (Arachnida: Pseudoscorpionida)

David W. Zeh
Evolution
Vol. 41, No. 5 (Sep., 1987), pp. 1072-1087
DOI: 10.2307/2409192
Stable URL: http://www.jstor.org/stable/2409192
Page Count: 16
  • Read Online (Free)
  • Download ($4.00)
  • Subscribe ($19.50)
  • 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.
Aggression, Density, and Sexual Dimorphism in Chernetid Pseudoscorpions (Arachnida: Pseudoscorpionida)
Preview not available

Abstract

The determinants of sexual dimorphism in a family of false scorpions (Pseudoscorpionida: Chernetidae) were investigated experimentally and with a literature analysis of comparative morphometric and habitat data. Species vary in the extent to which males and females differ in size of the pedipalps, and, in particular, in size of the pedipalpal chelae. A statistical analysis of dimorphism patterns within the Chernetidae suggests that dimorphism is a highly variable condition, relatively unconstrained by phylogenetic influences. The evolution of species with enlarged male pedipalps appears to be associated with a change from nonpairing to pairing sperm-transfer behavior and with aggressive mate acquisition by males. Experiments with Dinocheirus arizonensis demonstrate a strong correlation between male combat ability and chela size. Manipulations also suggest that superior combat ability of large males results in increased mating success only under high-density conditions. The greater success in spermatophore transfer among large males can be attributed to increased opportunity at high density for large males to interrupt matings and aggressively displace smaller males. Comparative analysis showed a positive correlation between density and enlarged male chela size across chernetid species.

Page Thumbnails

  • Thumbnail: Page 
1072
    1072
  • Thumbnail: Page 
1073
    1073
  • Thumbnail: Page 
1074
    1074
  • Thumbnail: Page 
1075
    1075
  • Thumbnail: Page 
1076
    1076
  • Thumbnail: Page 
1077
    1077
  • Thumbnail: Page 
1078
    1078
  • Thumbnail: Page 
1079
    1079
  • Thumbnail: Page 
1080
    1080
  • Thumbnail: Page 
1081
    1081
  • Thumbnail: Page 
1082
    1082
  • Thumbnail: Page 
1083
    1083
  • Thumbnail: Page 
1084
    1084
  • Thumbnail: Page 
1085
    1085
  • Thumbnail: Page 
1086
    1086
  • Thumbnail: Page 
1087
    1087