Novel fungal disease in complex leaf-cutting ant societies

Authors

  • DAVID P. HUGHES,

    Corresponding author
    1. 1 Department of Biology, Centre for Social Evolution, University of Copenhagen, Copenhagen, Denmark, 2Department of Organismal, Evolutionary Biology, Harvard University, Cambridge, U.S.A. School of Bioscience, University of Exeter, Exeter, U.K.3CAB International, U.K. Centre, Silwood Park, Ascot, Berkshire, U.K., 4Mycology Laboratory, National Center for Genetic Engineering and Biotechnology, Science Park, Pathum Thani, Thailand and 5Institute for Evolution and Biodiversity, Westfälische Wilhelms-Universität, Münster, Germany
    Search for more papers by this author
  • 1,2 HARRY C. EVANS,

    1. 1 Department of Biology, Centre for Social Evolution, University of Copenhagen, Copenhagen, Denmark, 2Department of Organismal, Evolutionary Biology, Harvard University, Cambridge, U.S.A. School of Bioscience, University of Exeter, Exeter, U.K.3CAB International, U.K. Centre, Silwood Park, Ascot, Berkshire, U.K., 4Mycology Laboratory, National Center for Genetic Engineering and Biotechnology, Science Park, Pathum Thani, Thailand and 5Institute for Evolution and Biodiversity, Westfälische Wilhelms-Universität, Münster, Germany
    Search for more papers by this author
  • 3 NIGEL HYWEL-JONES,

    1. 1 Department of Biology, Centre for Social Evolution, University of Copenhagen, Copenhagen, Denmark, 2Department of Organismal, Evolutionary Biology, Harvard University, Cambridge, U.S.A. School of Bioscience, University of Exeter, Exeter, U.K.3CAB International, U.K. Centre, Silwood Park, Ascot, Berkshire, U.K., 4Mycology Laboratory, National Center for Genetic Engineering and Biotechnology, Science Park, Pathum Thani, Thailand and 5Institute for Evolution and Biodiversity, Westfälische Wilhelms-Universität, Münster, Germany
    Search for more papers by this author
  • 4,5 JACOBUS J. BOOMSMA,

    1. 1 Department of Biology, Centre for Social Evolution, University of Copenhagen, Copenhagen, Denmark, 2Department of Organismal, Evolutionary Biology, Harvard University, Cambridge, U.S.A. School of Bioscience, University of Exeter, Exeter, U.K.3CAB International, U.K. Centre, Silwood Park, Ascot, Berkshire, U.K., 4Mycology Laboratory, National Center for Genetic Engineering and Biotechnology, Science Park, Pathum Thani, Thailand and 5Institute for Evolution and Biodiversity, Westfälische Wilhelms-Universität, Münster, Germany
    Search for more papers by this author
  • and 1,2 SOPHIE A. O. ARMITAGE 1,2

    1. 1 Department of Biology, Centre for Social Evolution, University of Copenhagen, Copenhagen, Denmark, 2Department of Organismal, Evolutionary Biology, Harvard University, Cambridge, U.S.A. School of Bioscience, University of Exeter, Exeter, U.K.3CAB International, U.K. Centre, Silwood Park, Ascot, Berkshire, U.K., 4Mycology Laboratory, National Center for Genetic Engineering and Biotechnology, Science Park, Pathum Thani, Thailand and 5Institute for Evolution and Biodiversity, Westfälische Wilhelms-Universität, Münster, Germany
    Search for more papers by this author

David P. Hughes, Centre for Social Evolution, Department of Biology, University of Copenhagen, Universitetsparken 15, 2100 Copenhagen, Denmark. E-mail: d.p.hughes@exeter.ac.uk

Abstract

Abstract 1. The leaf-cutting ants practise an advanced system of mycophagy where they grow a fungus as a food source. As a consequence of parasite threats to their crops, they have evolved a system of morphological, behavioural, and chemical defences, particularly against fungal pathogens (mycopathogens).

2. Specific fungal diseases of the leaf-cutting ants themselves have not been described, possibly because broad spectrum anti-fungal defences against mycopathogens have reduced their susceptibility to entomopathogens.

3. Using morphological and molecular tools, the present study documents three rare infection events of Acromyrmex and Atta leaf-cutting ants by Ophiocordyceps fungi, agenus of entomopathogens that is normally highly specific in its host choice.

4. As leaf-cutting ants have been intensively studied, the absence of prior records of Ophiocordyceps suggests that these infections may be a novel event and that switching from one host to another is possible. To test the likelihood of this hypothesis, host switching was experimentally induced, and successfully achieved, among five distinct genera of ants, one of which was in a different sub-family than the leaf-cutter ants.

5. Given the substantial differences among the five host ants, the ability of Ophiocordyceps to shift between such distant hosts is remarkable; the results are discussed in the context of ant ecological immunology and fungal invasion strategies.

Ancillary