Food quantity shapes life history and survival strategies in Daphnia magna (Cladocera)
Life history and demographic responses to different food regimes were investigated in three clones of Daphnia magna. Green alga Scenedesmus obliquus served as food source and was given in five amounts, which covered the range from near threshold to excess food concentrations, from 0.05 through 0.15, 0.5, 1.5 to 4.5 mg C l−1. The animals were kept under given food regime from first instar until their natural death. Food regime had a significant effect on Daphnia survival, which was shortest under the highest food regime. However, the response in expected reproduction of an individual differed between clones, with one benefiting more from higher food supply than the others. Life history trade-offs were seen as shortened lifespan versus higher investments in early reproduction.
KeywordsLifespan Life history Food regime Daphnia
We want to thank Joanna Pijanowska and Cristian Gudasz, and the two anonymous reviewers for the valuable comments, which helped to improve the manuscript. This study was supported by Polish Committee for Scientific Research grant N304 005 32/0647.
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