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Food web topology and parasites in the pelagic zone of a subarctic lake
Author(s) -
Amundsen PerArne,
Lafferty Kevin D.,
Knudsen Rune,
Primicerio Raul,
Klemetsen Anders,
Kuris Armand M.
Publication year - 2009
Publication title -
journal of animal ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.134
H-Index - 157
eISSN - 1365-2656
pISSN - 0021-8790
DOI - 10.1111/j.1365-2656.2008.01518.x
Subject(s) - trophic level , food web , pelagic zone , biology , ecology , food chain , subarctic climate , host (biology)
Summary1 Parasites permeate trophic webs with their often complex life cycles, but few studies have included parasitism in food web analyses. Here we provide a highly resolved food web from the pelagic zone of a subarctic lake and explore how the incorporation of parasites alters the topology of the web. 2 Parasites used hosts at all trophic levels and increased both food‐chain lengths and the total number of trophic levels. Their inclusion in the network analyses more than doubled the number of links and resulted in an increase in important food‐web characteristics such as linkage density and connectance. 3 More than half of the parasite taxa were trophically transmitted, exploiting hosts at multiple trophic levels and thus increasing the degree of omnivory in the trophic web. 4 For trophically transmitted parasites, the number of parasite–host links exhibited a positive correlation with the linkage density of the host species, whereas no such relationship was seen for nontrophically transmitted parasites. Our findings suggest that the linkage density of free‐living species affects their exposure to trophically transmitted parasites, which may be more likely to adopt highly connected species as hosts during the evolution of complex life cycles. 5 The study supports a prominent role for parasites in ecological networks and demonstrates that their incorporation may substantially alter considerations of food‐web structure and functioning.