Trading off the ability to exploit rich versus poor food quality

Authors

  • Alan J. Tessier,

    Corresponding author
    1. W. K. Kellogg Biological Station, Michigan State University, Hickory Corners MI 49060, USA.
      * Correspondence: Tel.:+616 671 2338. Fax:+616 671 2104. E-mail: tessier@kbs.msu.edu
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  • Pamela Woodruff

    1. W. K. Kellogg Biological Station, Michigan State University, Hickory Corners MI 49060, USA.
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  • Editor, L. Blaustein

* Correspondence: Tel.:+616 671 2338. Fax:+616 671 2104. E-mail: tessier@kbs.msu.edu

Abstract

Abstract Lakes differ in the quality of food for planktonic grazers, but whether grazers adapt to this resource heterogeneity is poorly studied. We test for evidence of specialization to resource environment within a guild of suspension feeding daphniids inhabiting lakes that differ in food web structure. Using bioassays, we demonstrate that food quality for grazers increases from deep to shallow to temporary lakes, which also represents a gradient of increasing predation risk. We compare growth rates and reproductive performance of daphniid taxa specific to each of the three lake types and find they differ greatly in minimum resource requirements, and in sensitivity to the resource gradient. These differences express a trade-off in ability to exploit rich vs. poor resources. Taxa from deep lakes, poor in resources, have low minimal needs, but they do relatively poorly in rich resource environments. We conclude that grazer distribution is consistent with an adaptive match of exploitation ability to resource environments.

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