title: Temperature driven changes in the diet preference of omnivorous copepods: no more meat when it's hot?
abstract: Herbivory is more prevalent in the tropics than at higher latitudes. If differences in ambient temperature are the direct cause for this phenomenon, then the same pattern should be visible in a seasonal gradient, as well as in experiments manipulating temperature. Using (15)N stable isotope analyses of natural populations of the copepod Temora longicornis we indeed observed seasonal differences in the trophic level of the copepod and a decrease in trophic level with increasing temperature. In a grazing experiment, with a mixed diet of the cryptophyte Rhodomonas salina and the heterotrophic dinoflagellate Oxyrrhis marina, T. longicornis preferred the cryptophyte at higher temperatures, whereas at lower temperatures it preferred the non-autotrophic prey. We explain these results by the higher relative carbon content of primary producers compared to consumers, in combination with the higher demand for metabolic carbon at higher temperatures. Thus, currently increasing temperatures may cause changes in dietary preferences of many consumers.
authors.affiliation: Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung, Biologische Anstalt Helgoland, Postfach 180, 27483, Helgoland, Germany.|University of Bremen, Bremen, Germany.
authors.forename: Maarten
authors.initials: M
authors.lastname: Boersma
authors.affiliation: Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung, Biologische Anstalt Helgoland, Postfach 180, 27483, Helgoland, Germany.
authors.forename: K Avarachen
authors.initials: KA
authors.lastname: Mathew
authors.affiliation: Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung, Bremerhaven, Germany.
authors.forename: Barbara
authors.initials: B
authors.lastname: Niehoff
authors.affiliation: Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung, Biologische Anstalt Helgoland, Postfach 180, 27483, Helgoland, Germany.
authors.forename: Katherina L
authors.initials: KL
authors.lastname: Schoo
authors.affiliation: University of Bremen, Bremen, Germany.|Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung, Bremerhaven, Germany.
authors.forename: Rita M
authors.initials: RM
authors.lastname: Franco-Santos
authors.affiliation: Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung, Biologische Anstalt Helgoland, Postfach 180, 27483, Helgoland, Germany.
authors.forename: Cédric L
authors.initials: CL
authors.lastname: Meunier
mesh_terms: D000818:Animals; D033342:Copepoda / Q000502:physiology*; D044785:Cryptophyta / Q000737:chemistry*; D004141:Dinoflagellida / Q000737:chemistry*; D020387:Food Chain; D005518:Food Preferences; D006358:Hot Temperature
keywords: Global warming; grazing; homeostasis; metabolism; stoichiometry; zooplankton