Increasing dietary specialization is an inherently risky strategy because it increases a species' vulnerability to resource depletion. However, risks associated with dietary specialization may be offset by increased performance when feeding on preferred prey. Although rarely demonstrated, highly specialized species are expected to outperform generalists when feeding on their preferred prey, whereas generalists are predicted to have more similar performance across a range of different prey. To test this theory, we compared the growth rates of two obligate coral-feeding butterflyfishes (Chaetodon trifascialis and Chaetodon plebeius) maintained on exclusive diets of preferred vs nonpreferred prey. In the field, C. trifascialis was the most specialized species, feeding almost exclusively on just one coral species, Acropora hyacinthus. C. plebeius meanwhile, was much less specialized, but fed predominantly on Pocillopora damicornis. During growth experiments, C. trifascialis grew fastest when feeding on A. hyacinthus and did not grow at all when feeding on less preferred prey (P. damicornis and Porites cylindrica). C. plebeius performed equally well on both A. hyacinthus and P. damicornis (its preferred prey), but performed poorly when feeding on P. cylindrica. Both butterflyfishes select coral species that maximize juvenile growth, but contrary to expectations, the more specialized species (C. trifascialis) did not outperform the generalist species (C. plebeius) when both consumed their preferred prey. Increased dietary specialization, therefore, appears to be a questionable strategy, as there was no evidence of any increased benefits to offset increases in susceptibility to disturbance.
|Original language||English (US)|
|Number of pages||6|
|Journal||Behavioral Ecology and Sociobiology|
|State||Published - Apr 2008|
Bibliographical noteFunding Information:
Acknowledgements We thank Geoff Jones, Howard Choat, and three anonymous reviewers for their comments, which greatly improved the manuscript; and D deVere, D Pratchett, and J Pitt for the assistance in the field. This work was supported by a National Science Foundation (USA) Graduate Research Fellowship to MLB. These experiments comply with the laws of the country in which they were performed.
- Coral reef fishes
- Ecological versatility
- Feeding selectivity
- Growth rates
- Resource selection
ASJC Scopus subject areas
- Ecology, Evolution, Behavior and Systematics
- Animal Science and Zoology