Evolution of larval foraging behaviour in Drosophila and its effects on growth and metabolic rates

Authors

  • Laurence D. Mueller,

    Corresponding author
    1. Department of Ecology and Evolutionary Biology, University of California, Irvine, Irvine, California, U.S.A. and
      *Dr L. D. Mueller, Department of Ecology and Evolutionary Biology, University of California, Irvine, CA 92697, U.S.A. Tel.: +1 949 824 4744; fax: +1 949 824 2181; e-mail: ldmuelle@uci.edu
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  • Donna G. Folk,

    1. Department of Biology, College of William and Mary, Williamsburg, Virginia, U.S.A.
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  • Ngoc Nguyen,

    1. Department of Ecology and Evolutionary Biology, University of California, Irvine, Irvine, California, U.S.A. and
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  • Phuong Nguyen,

    1. Department of Ecology and Evolutionary Biology, University of California, Irvine, Irvine, California, U.S.A. and
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  • Phi Lam,

    1. Department of Ecology and Evolutionary Biology, University of California, Irvine, Irvine, California, U.S.A. and
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  • Michael R. Rose,

    1. Department of Ecology and Evolutionary Biology, University of California, Irvine, Irvine, California, U.S.A. and
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  • Timothy Bradley

    1. Department of Ecology and Evolutionary Biology, University of California, Irvine, Irvine, California, U.S.A. and
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*Dr L. D. Mueller, Department of Ecology and Evolutionary Biology, University of California, Irvine, CA 92697, U.S.A. Tel.: +1 949 824 4744; fax: +1 949 824 2181; e-mail: ldmuelle@uci.edu

Abstract

Abstract.  The evolution of foraging in Drosophila melanogaster (Meigen) is studied using outbred populations that had been differentiated using laboratory selection. The foraging behaviour of Drosophila larvae is measured using the foraging path length of 72-h-old larvae. The foraging path length is the distance travelled by foraging larvae over 5 min. Populations of Drosophila selected for rapid development show significantly greater path lengths than their controls. Populations of Drosophila selected for resistance to ammonia and urea in their larval food have shorter path lengths than their controls. Individuals in the ammonia-resistant populations are smaller than those in the control populations, but the size-adjusted metabolic rates are not significantly different. A simple model is proposed suggesting that changes in larval foraging behaviour may be a means for Drosophila larvae to adapt to new environments that require additional maintenance energy. In the ammonia-selected populations, crucial tests of these ideas will have to be conducted in environments with ammonia.

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