High parasite diversity in the amphipod Gammarus lacustris in a subarctic lake

Abstract Amphipods are often key species in aquatic food webs due to their functional roles in the ecosystem and as intermediate hosts for trophically transmitted parasites. Amphipods can also host many parasite species, yet few studies address the entire parasite community of a gammarid population,...

Full description

Bibliographic Details
Published in:Ecology and Evolution
Main Authors: Jenny C. Shaw, Eirik H. Henriksen, Rune Knudsen, Jesper A. Kuhn, Armand M. Kuris, Kevin D. Lafferty, Anna Siwertsson, Miroslava Soldánová, Per‐Arne Amundsen
Format: Article in Journal/Newspaper
Language:English
Published: Wiley 2020
Subjects:
Online Access:https://doi.org/10.1002/ece3.6869
https://doaj.org/article/1318bb08f8354c6d91c836f3c5934524
Description
Summary:Abstract Amphipods are often key species in aquatic food webs due to their functional roles in the ecosystem and as intermediate hosts for trophically transmitted parasites. Amphipods can also host many parasite species, yet few studies address the entire parasite community of a gammarid population, precluding a more dynamic understanding of the food web. We set out to identify and quantify the parasite community of Gammarus lacustris to understand the contributions of the amphipod and its parasites to the Takvatn food web. We identified seven parasite taxa: a direct life cycle gregarine, Rotundula sp., and larval stages of two digenean trematode genera, two cestodes, one nematode, and one acanthocephalan. The larval parasites use either birds or fishes as final hosts. Bird parasites predominated, with trematode Plagiorchis sp. having the highest prevalence (69%) and mean abundance (2.7). Fish parasites were also common, including trematodes Crepidostomum spp., nematode Cystidicola farionis, and cestode Cyathocephalus truncatus (prevalences 13, 6, and 3%, respectively). Five parasites depend entirely on G. lacustris to complete their life cycle. At least 11.4% of the overall parasite diversity in the lake was dependent on G. lacustris, and 16% of the helminth diversity required or used the amphipod in their life cycles. These dependencies reveal that in addition to being a key prey item in subarctic lakes, G. lacustris is also an important host for maintaining parasite diversity in such ecosystems.