title: Sensitivity of Daphnia species to phosphorus-deficient diets.
abstract: The life history of freshwater cladocerans such as Daphnia spp. is strongly affected by their environment. Factors such as temperature, food quantity and even the presence or absence of predators influence growth, reproduction and morphology of individuals. Recently, it has also become clear that the quality of the food can affect various life history traits of Daphnia. More specifically, the effect of the elemental composition of algae, expressed as the C:P ratio, has been studied intensively. Daphnia species differ in their response to differences in the C:P ratio of their food. Until now, it has been unclear whether these species differences are driven by phylogenetic constraints or by adaptation to particular environmental conditions. Here we present laboratory experiments with 12 Daphnia species from three different subgenera originating from a broad range of habitats. We compared somatic growth rates and sensitivity to variation in the nutrient stoichiometry of the food with habitat parameters, taking into account the phylogenetic history of the species. No associations between fitness and habitat parameters were detected. However, we found a trade-off between sensitivity to P-deficient diets and the maximum growth rate on a P-sufficient diet. In several cases, this trade-off helps to explain the association between species distribution and habitat parameters. We observed no correlation of the sensitivity to P limitation with the phylogenetic history of the genus Daphnia. Thus, we conclude that the differential responses among Daphnia species to variation in P content in food were driven mainly by adaptations to their local habitats, and are not constrained by deep evolutionary patterns.
authors.affiliation: Department of Ecology and Evolution, Institute for Ecology, Evolution and Diversity, Goethe-University Frankfurt am Main, Siesmayerstrasse 70, 60054, Frankfurt am Main, Germany. Seidendorf@gmx.de
authors.forename: Bernd
authors.initials: B
authors.lastname: Seidendorf
authors.forename: Nadine
authors.initials: N
authors.lastname: Meier
authors.forename: Adam
authors.initials: A
authors.lastname: Petrusek
authors.forename: Maarten
authors.initials: M
authors.lastname: Boersma
authors.forename: Bruno
authors.initials: B
authors.lastname: Streit
authors.forename: Klaus
authors.initials: K
authors.lastname: Schwenk
mesh_terms: D000818:Animals; D003621:Daphnia / Q000254:growth & development / Q000378:metabolism / Q000502:physiology*; D016226:Phosphorus, Dietary / Q000378:metabolism*; D010802:Phylogeny; D011157:Population Dynamics; D013045:Species Specificity
chemical_list: D016226:Phosphorus, Dietary