Behavioral Ecology and Sociobiology

, Volume 64, Issue 3, pp 485–491 | Cite as

How do weaponless male fiddler crabs avoid aggression?

  • Isobel Booksmythe
  • Richard N. C. Milner
  • Michael D. Jennions
  • Patricia R. Y. Backwell
Original Paper


Mimicry of females enables weaker males in many species to avoid intrasexual aggression. In fiddler crabs (Uca annulipes), males use their major claw in aggressive interactions to acquire and defend a territory. Males that have autotomised their major claw will be disadvantaged in fighting, but might use their temporary resemblance to females to avoid costly aggressive encounters with other males. We investigated whether: (1) courting males mistake clawless male fiddler crabs for females; (2) clawless males are able to acquire, defend and retain territories as successfully as intact males; and (3) clawless males are more cautious than intact males. Clawless and intact males differed in burrow acquisition methods and fighting behaviour, but were equally successful at acquiring and retaining burrows. While courting males treated clawless males as female, we found no evidence that clawless males mimic the behaviour of females, or that they exploit the advantage of their mistaken identity. Clawless males further appear to avoid male aggression by altering their territorial strategies to minimise the potential for conflict.


Autotomy Female mimicry Fiddler crab Territory acquisition Territory defence 



We thank Jessica Bolton and Tanya Detto for helpful suggestions and discussion. This work was supported by an Australian Research Council Discovery Grant (PRYB) and the Australian National University Fieldwork Funding Initiative (IB). Permission to work in the Inhaca marine reserve was provided by the Inhaca Marine Biological Station, Eduardo Mondlane University, Mozambique.


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Copyright information

© Springer-Verlag 2009

Authors and Affiliations

  • Isobel Booksmythe
    • 1
  • Richard N. C. Milner
    • 1
  • Michael D. Jennions
    • 1
  • Patricia R. Y. Backwell
    • 1
  1. 1.Research School of Biology (Botany and Zoology)The Australian National UniversityCanberraAustralia

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