Cookies Policy

This site uses cookies. By continuing to browse the site you are agreeing to our use of cookies.

I accept this policy

Find out more here

Asymmetry of Leg Size and Differential Leg Usage in the Sand Fiddler Crab, Uca Pugilator

No metrics data to plot.
The attempt to load metrics for this article has failed.
The attempt to plot a graph for these metrics has failed.
The full text of this article is not currently available.

Brill’s MyBook program is exclusively available on BrillOnline Books and Journals. Students and scholars affiliated with an institution that has purchased a Brill E-Book on the BrillOnline platform automatically have access to the MyBook option for the title(s) acquired by the Library. Brill MyBook is a print-on-demand paperback copy which is sold at a favorably uniform low price.

Access this article

+ Tax (if applicable)
Add to Favorites
You must be logged in to use this functionality

image of Journal of Crustacean Biology

Abstract In fiddler crabs, males develop profound left-right asymmetry as a large claw grows opposite a small feeding appendage. Females are symmetrical, with paired small feeding appendages. The claw, used in signaling and contests, may favor adaptive responses in walking legs. This study of sand fiddler crabs, Uca pugilator, investigates differences in leg size and proportion: 1) between major (with the claw) and minor (without the claw) sides, using 404 males from which a pair of legs was removed, and 2) between males and females, using 1085 adults from which a single leg was removed. Among males, only the first walking leg was longer on the major side. This was due to the much greater length of the merus, a proximal long segment that is held parallel to the ground. The merus was longer on the major side in all walking legs. This may permit the claw to be extended away from the body without loss of balance when males either engage in contests over breeding burrows or wave the claw to attract females to burrows. More distal segments, the long carpus + manus, held approximately perpendicular to the ground, and the dactyl, anchoring the leg to the ground, were longer on the minor side, resulting in longer minor-side legs for the second to fourth pairs of legs. Female legs were proportioned like those on the minor side, with a long carpus + manus relative to the merus. However, rear legs of females are relatively long, which may facilitate holding an egg mass above the surface. In males, minor-side legs were more massive than major side legs. This suggests a greater work load on the minor side, as during contests that escalate to interlocking of claws, where minor side legs are important in pushing the opponent. Legs of females were more massive than those of males. The greater mass of female legs is not necessary to support an egg mass, which weighs less than the claw of a similar-sized male. The stouter legs of females may facilitate digging out of breeding burrows.

Affiliations: 1: (DKM:; AEP: Department of Biology, P. O. Box 8042, Georgia Southern University, Statesboro, Georgia 30460, U.S.A


Full text loading...


Data & Media loading...

1. Bosc L. A G. 1802 "Histoire naturelle des Crustacs, contenant leur description et leurs moeurs, avec figures dessines d'aprs nature, 1: 1-258, pls. 1-8; 2, 1-296, pls. 9-18." Paris: de Guilleminet
2. Christy J. H. 1982 "Burrow structure and use in the sand fiddler crab, Uca pugilator (Bosc)." Animal Behaviour Vol 30 687 694
3. Crane J. 1975 "Fiddler Crabs of the World." Princeton University Press, Princeton
4. Freeman A. 2004 "Left v right." BBC Wildilfe Vol 22 62 65
5. Govind C. K. , Quigley M. M. , Mearow K. M. 1986 "The closer muscle in the dimorphic claws of male fiddler crabs." Biological Bulletin Vol 170 481 493
6. Hartnoll R. G. 1974 "Variation in growth pattern between some secondary sexual characters in crabs (Decapoda Brachyura)." Crustaceana Vol 27 131 136
7. Herbst J. F W. 1782-1804 "Versuch einer Naturgeschichte der Krabben und Krebse nebst einer systematischen Beschreibung ihrer verschiedenen Arten, volume 1 (1782-1790)." pp. 1-274, pls. 1-21. G. A Lange, Berlin; J. C. Fuessly, Zrich
8. Huxley J. S. 1932 "Problems of Relative Growth." Methuen, London
9. Huxley J. S. , Callow F. S. 1933 "A note of the asymmetry of male fiddler-crabs (Uca pugilator)." W. Roux' Archives Entwicklungsmechanik Vol 129 379 392
10. Levinton J. S. , Judge M. L. , Kurdziel J. P. 1995 "Functional differences between major and minor claws of fiddler crabs (Uca, family Ocypodidae, Order Decapoda, Subphylum Crustacea): a result of selection or developmental constraint?." Journal of Experimental Maine Biology and Ecology Vol 193 147 160
11. McLain D. K. , Pratt A. 2007 "Approach of females to magnified reflections indicates that claw size of waving fiddler crabs correlates with signaling effectiveness." Journal of Experimental Marine Biology & Ecology Vol 343 227 238
12. McLain D. K. , Pratt A. , Berry A. S. 2003 "Predation by red-jointed fiddler crabs on congeners: interaction between body size and positive allometry of the sexually selected claw." Behavioral Ecology Vol 14 741 747
13. Miller D. C. 1973 "Growth in Uca, 1. Ontogeny of asymmetry in Uca pugilator (Bosc) (Decapoda, Ocypodidae)." Crustaceana Vol 24 119 131
14. Morgan T. H. 1923 "The development of asymmetry in the fiddler crab." American Naturalist Vol 57 269 273
15. Morgan T. H. 1924 "The artificial induction of symmetrical claws in male fiddler crabs." American Naturalist Vol 58 289 295
16. Pratt A. E. , McLain D. K. 2002 "Antisymmetry in male fiddler crabs and the decision to feed or breed." Functional Ecology Vol 16 89 98
17. Pratt A. E. , McLain D. K. 2006 "How dear is my enemy: intruder-resident and resident-resident encounters in male sand fiddler crabs (Uca pugilator)." Behaviour Vol 143 597 617
18. Pratt A. E. , McLain D. K. , Lathrop G. R. 2003 "The assessment game in fiddler crab contests for breeding burrows." Animal Behaviour Vol 65 945 955
19. Rathbun M. J. 1900 "Results of the Branner-Agassiz expedition to Brazil. I. The decapod and stomatopod Crustacea." Proceedings of the Washington Academy of Sciences Vol 2 133 156
20. Reiss M. J. 1989 "The Allometry of Growth and Reproduction." Cambridge University Press, Cambridge
21. Sokal R. R. , Rohlf F. J. 1995 "Biometry." W. H. Freeman, New York
22. Takeda S. , Murai M. 1993 "Asymmetry in male fiddler crabs is related to the basic pattern of claw-waving display." Biological Bulletin Vol 184 203 208
23. Tazelaar M. A. 1933 "A study of relative growth in Uca pugnax." W. Roux' Archives Entwicklungsmechanik Vol 129 393 401
24. Tessier G. 1960 "Relative growth,." pp. 537-560 In, T. H. Waterman (ed.), The Physiology of Crustacea 1. Academic Press, New York
25. Wright S. 1968 "Evolution and the Genetics of Populations, Volume 1: Genetic and Biometric Foundations." University of Chicago Press, Chicago
26. Yerkes R. M. 1901 "A study of variation in the fiddler crab Gelasimus pugilator Latr." Proceedings American Academy of Arts and Sciences Vol 36 417 442

Article metrics loading...



Can't access your account?
  • Tools

  • Add to Favorites
  • Printable version
  • Email this page
  • Subscribe to ToC alert
  • Get permissions
  • Recommend to your library

    You must fill out fields marked with: *

    Librarian details
    Your details
    Why are you recommending this title?
    Select reason:
    Journal of Crustacean Biology — Recommend this title to your library
  • Export citations
  • Key

  • Full access
  • Open Access
  • Partial/No accessInformation