Present address: Integrative Biology, University of Texas at Austin, 1 University Station C0930, Austin, TX 78712, USA
Individual-level diet variation in four species of Brazilian frogs
Article first published online: 31 MAR 2009
© 2009 The Authors. Journal compilation © 2009 British Ecological Society
Journal of Animal Ecology
Volume 78, Issue 4, pages 848–856, July 2009
How to Cite
Araújo, M. S., Bolnick, D. I., Martinelli, L. A., Giaretta, A. A. and Dos Reis, S. F. (2009), Individual-level diet variation in four species of Brazilian frogs. Journal of Animal Ecology, 78: 848–856. doi: 10.1111/j.1365-2656.2009.01546.x
- Issue published online: 4 JUN 2009
- Article first published online: 31 MAR 2009
- Received 15 August 2008; accepted 25 February 2009Handling Editor: Ryan Norris
- carbon stable isotopes;
- individual specialization;
- niche variation;
- Niche Variation Hypothesis
- 1Many natural populations exploiting a wide range of resources are actually composed of relatively specialized individuals.
- 2This interindividual variation is thought to be a consequence of the invasion of ‘empty’ niches in depauperate communities, generally in temperate regions. If individual niches are constrained by functional trade-offs, the expansion of the population niche is only achieved by an increase in interindividual variation, consistent with the ‘niche variation hypothesis’.
- 3According to this hypothesis, we should not expect interindividual variation in species belonging to highly diverse, packed communities.
- 4In the present study, we measured the degree of interindividual diet variation in four species of frogs of the highly diverse Brazilian Cerrado, using both gut contents and δ13C stable isotopes.
- 5We found evidence of significant diet variation in the four species, indicating that this phenomenon is not restricted to depauperate communities in temperate regions.
- 6The lack of correlations between the frogs’ morphology and diet indicate that trade-offs do not depend on the morphological characters measured here and are probably not biomechanical. The nature of the trade-offs remains unknown, but are likely to be cognitive or physiological.
- 7Finally, we found a positive correlation between the population niche width and the degree of diet variation, but a null model showed that this correlation can be generated by individuals sampling randomly from a common set of resources. Therefore, albeit consistent with, our results cannot be taken as evidence in favour of the niche variation hypothesis.