Evol Ecol Res 8: 843-857 (2006)     Full PDF if your library subscribes.

Inherited differences in foraging behaviour in the offspring of two forms of lacustrine brook charr

S. Sacotte and P. Magnan*

Groupe de recherche sur les écosystèmes aquatiques, Université du Québec à Trois-Rivières, CP 500, Trois-Rivières, Québec G9A 5H7, Canada

Author to whom all correspondence should be addressed.
e-mail: pierre.magnan@uqtr.ca

ABSTRACT

Hypothesis: Behavioural differences observed in the field between littoral and pelagic brook charr, Salvelinus fontinalis (Mitchill), persist in their progeny when progeny are reared in a common-garden laboratory environment.

Methods: Young-of-the-year of the pelagic and littoral forms were raised in the laboratory. Experiments began when the fry were approximately 4 months after the first feeding. Swimming and foraging behaviour, as well as the morphological characteristics of individuals, were measured.

Results: Morphological characters used to identify brook charr ecotypes in the field (pectoral fin length and dorsal fin base length) were inherited in the progeny. Littoral offspring exhibited a deeper body and longer pectoral fins and dorsal fin base than pelagic offspring. Furthermore, the foraging experiments indicated that naive littoral offspring were significantly more efficient than pelagic offspring when feeding on bloodworms (higher capture rate and lower rejection rate). There were no significant differences between the pelagic and littoral individuals when feeding on Daphnia sp. Although subtle, these results suggest that there is a genetic component to trophic polymorphism in brook charr and that behavioural diversification is not constrained by morphological traits: the few differences in feeding-related morphology between littoral and pelagic individuals cannot explain the observed differences in the capture and rejection rates of bloodworms.

Keywords: activity pattern, brook charr, capture rate, foraging behaviour, morphology, swimming behaviour, trophic polymorphism.

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        © 2006 Pierre Magnan. All EER articles are copyrighted by their authors. All authors endorse, permit and license Evolutionary Ecology Ltd. to grant its subscribing institutions/libraries the copying privileges specified below without additional consideration or payment to them or to Evolutionary Ecology, Ltd. These endorsements, in writing, are on file in the office of Evolutionary Ecology, Ltd. Consult authors for permission to use any portion of their work in derivative works, compilations or to distribute their work in any commercial manner.

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