Costs of bearing a sexually selected ornamental weapon in a fiddler crab
Article first published online: 11 JAN 2007
Volume 21, Issue 1, pages 154–161, February 2007
How to Cite
ALLEN, B. J. and LEVINTON, J. S. (2007), Costs of bearing a sexually selected ornamental weapon in a fiddler crab. Functional Ecology, 21: 154–161. doi: 10.1111/j.1365-2435.2006.01219.x
- Issue published online: 11 JAN 2007
- Article first published online: 11 JAN 2007
- Received 17 May 2006; revised 8 August 2006; accepted 25 September 2006Editor: Mike Siva-Jothy
- energetic constraint;
- locomotor performance;
- Uca pugilator
- 1Sexually selected structures with dual function of combat and display are likely to be honest signals of male quality to opponents and mates, but should be costly to produce and maintain.
- 2Male fiddler crabs use a single greatly enlarged claw as both a weapon in agonistic contests with other males and an ornament to attract females for mating. Given the extreme size of this structure (up to half the total body mass), there is surprisingly little evidence for costs as predicted by theory.
- 3We experimentally investigated several potential costs of the large claw to male sand fiddler crabs Uca pugilator. Mass-specific metabolic rates were significantly higher and treadmill endurance capacity significantly lower for males bearing an intact major claw compared with those without.
- 4In contrast, presence of the claw did not affect maximal sprint speeds, suggesting that the massive structure does not compromise the ability of male crabs to evade predators. These counterintuitive results conform to recent theoretical models of energy costs of locomotion.
- 5Our study provides empirical support for a key assumption of sexual selection theory – energetic and endurance-related locomotor costs incurred while bearing this ornamental weapon act in opposition to sexual selection favouring larger claws.