Handedness in fiddler crab fights

Perez, D. M.; Heatwole, S. J.; Morrell, L. J.; Backwell, P. R. Y.

Abstract

Asymmetric weapons are common in bilateral animals and, in some species, they can occur on either the left- or the right-hand side of the body (lateralization). Fiddler crabs (Uca spp, Decapoda: Ocypodidae) have an enlarged claw that is used in male–male combat over territories and in courtship displays. Males can be either right- or left-handed, and most species have a 1:1 ratio. Past studies have found little effect of handedness on fighting success, fight duration or other measures of combat. Here we show that, while handedness per se, does not affect fighting, handedness matching has a significant effect. In Uca mjoebergi, fights between different-handed males were more likely to escalate to grappling, suggesting that it is harder for the combatants to determine the winner. We suggest that the positioning of the claws during fighting creates distinct forces that result in different outcomes for same- versus different-handed fights. This can represent a strong selective pressure in populations with an uneven handedness distribution where the handedness minority will often engage in different-handed fights. We discuss these results in light of the selective forces that may act on handedness distribution in fiddler crabs.

Citation

Perez, D. M., Heatwole, S. J., Morrell, L. J., & Backwell, P. R. Y. (2015). Handedness in fiddler crab fights. Animal behaviour, 110(December), 99-104. https://doi.org/10.1016/j.anbehav.2015.09.012

• Journal Article Type: Article
• Acceptance Date: Aug 24, 2015
• Online Publication Date: Oct 23, 2015
• Publication Date: Dec 1, 2015
• Deposit Date: Oct 23, 2015
• Publicly Available Date: Nov 23, 2017
• Journal: Animal behaviour
• Print ISSN: 0003-3472
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 110
• Issue: December
• Pages: 99-104
• DOI: https://doi.org/10.1016/j.anbehav.2015.09.012
• Keywords: Body asymmetry; Fight costs; Fight outcome; Handedness distribution; Handedness matching
• Public URL: https://hull-repository.worktribe.com/output/380053
• Publisher URL: http://www.sciencedirect.com/science/article/pii/S0003347215003437
• Additional Information: Authors' accepted manuscript of article published in: Animal behaviour, 2015, v.110, December.