The reproductive role hypothesis explains trophic morphology dimorphism in the northern map turtle
Article first published online: 9 MAY 2008
© 2008 The Authors. Journal compilation © 2008 British Ecological Society
Volume 22, Issue 5, pages 824–830, October 2008
How to Cite
Bulté, G., Irschick, D. J. and Blouin-Demers, G. (2008), The reproductive role hypothesis explains trophic morphology dimorphism in the northern map turtle. Functional Ecology, 22: 824–830. doi: 10.1111/j.1365-2435.2008.01422.x
- Issue published online: 20 SEP 2008
- Article first published online: 9 MAY 2008
- Received 10 December 2007; accepted 2 April 2008; Handling Editor: Raoul van Damme
- bite force;
- body condition;
- reproductive output;
- reproductive role
- 1Sexually dimorphic traits often reflect factors limiting the reproductive success of animals. Thus, most sexually dimorphic traits can be directly linked to the reproductive role of each sex. Sexual dimorphism in trophic structures (e.g. beak, jaws, teeth), however, often lacks a direct link to reproduction.
- 2Trophic structures can be linked indirectly to reproductive allocation via energy acquisition. The reproductive role hypothesis (also known as the dimorphic niche hypothesis) posits such an indirect link, but has received heretofore little direct empirical support. We tested this hypothesis in a molluscivorous turtle exhibiting marked female-biased trophic morphology dimorphism.
- 3Bite force analysis showed that females have stronger jaws than males and dietary analysis revealed that females ingest snails closer to their maximum biting capacity than males. Body condition of both sexes and reproductive output of females increased with relative head width, indicating that fitness is tightly linked to head size and bite force.
- 4Our study provides strong evidence that reproductive role contributes to sexual dimorphism in trophic morphology. Our findings should apply to any animal in which energy intake is limited by trophic morphology.