Species abundance and the distribution of specialization in host–parasite interaction networks

Authors

  • DIEGO P. VÁZQUEZ,

    Corresponding author
    1. National Center for Ecological Analysis and Synthesis, University of California, 735 State St., Suite 300, Santa Barbara, CA 93101, USA;
    2. Centre d’Ecologie Fonctionnelle et Evolutive, U.M.R. 5175, 1919 Route de Mende, F-34293 Montpellier Cedex 5, France;
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  • ROBERT POULIN,

    1. Department of Zoology, University of Otago, PO Box 56, Dunedin, New Zealand; and
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  • BORIS R. KRASNOV,

    1. Ramon Science Center and Mitrani Department of Desert Ecology, Jacob Blaustein Institute for Desert Research, Ben-Gurion University of the Negev, PO Box 194, Mizpe Ramon 80600, Israel
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  • GEORGY I. SHENBROT

    1. Ramon Science Center and Mitrani Department of Desert Ecology, Jacob Blaustein Institute for Desert Research, Ben-Gurion University of the Negev, PO Box 194, Mizpe Ramon 80600, Israel
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Present address and correspondence: Diego P. Vázquez, Instituto Argentino de Investigaciones de las Zonas Áridas, Av. Ruiz Leal s/n, (5500) Mendoza, Argentina. Tel.: +54-261-4280080. Fax: +54-261-4287995. E-mail: dvazquez@lab.cricyt.edu.ar

Summary

  • 1Recent studies have evaluated the distribution of specialization in species interaction networks. Species abundance patterns have been hypothesized to determine observed topological patterns. We evaluate this hypothesis in the context of host–parasite interaction networks.
  • 2We used two independent series of data sets, one consisting of data for seven sites describing interactions between freshwater fish and their metazoan parasites and another consisting of data for 25 localities describing interactions between fleas and their mammalian hosts. We evaluated the influence of species abundance patterns on the distribution of specialization in these host–parasite interaction networks with the aid of null models.
  • 3In parallel with recent studies of plant–animal mutualistic networks, our analyses suggest that host–parasite interactions in these systems are highly asymmetric: specialist parasites tend to interact with hosts with high parasite richness, whereas hosts with low parasite richness tend to interact mainly with generalist parasites.
  • 4The observed distribution of specialization was predicted by a null model that assumed that species-specific probabilities of being assigned a link during the randomization process were roughly proportional to their relative abundance. Thus, abundant hosts tend to harbour richer parasite faunas, with a high proportion of rare specialists.

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