title: Nematomorph parasites indirectly alter the food web and ecosystem function of streams through behavioural manipulation of their cricket hosts.
abstract: Nematomorph parasites manipulate crickets to enter streams where the parasites reproduce. These manipulated crickets become a substantial food subsidy for stream fishes. We used a field experiment to investigate how this subsidy affects the stream community and ecosystem function. When crickets were available, predatory fish ate fewer benthic invertebrates. The resulting release of the benthic invertebrate community from fish predation indirectly decreased the biomass of benthic algae and slightly increased leaf break-down rate. This is the first experimental demonstration that host manipulation by a parasite can reorganise a community and alter ecosystem function. Nematomorphs are common, and many other parasites have dramatic effects on host phenotypes, suggesting that similar effects of parasites on ecosystems might be widespread.
authors.affiliation: The Hakubi Center for Advanced Research, Kyoto University, Sakyo-ku, Kyoto, Japan. takuya@species.jp
authors.forename: Takuya
authors.initials: T
authors.lastname: Sato
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Egusa
authors.forename: Keitaro
authors.initials: K
authors.lastname: Fukushima
authors.forename: Tomoki
authors.initials: T
authors.lastname: Oda
authors.forename: Nobuhito
authors.initials: N
authors.lastname: Ohte
authors.forename: Naoko
authors.initials: N
authors.lastname: Tokuchi
authors.forename: Katsutoshi
authors.initials: K
authors.lastname: Watanabe
authors.forename: Minoru
authors.initials: M
authors.lastname: Kanaiwa
authors.forename: Isaya
authors.initials: I
authors.lastname: Murakami
authors.forename: Kevin D
authors.initials: KD
authors.lastname: Lafferty
mesh_terms: D000818:Animals; D001522:Behavior, Animal; D018533:Biomass; D017753:Ecosystem; D005399:Fishes; D020387:Food Chain; D006135:Gryllidae / Q000469:parasitology*; D006374:Helminthiasis, Animal; D006376:Helminths / Q000469:parasitology*; D007448:Invertebrates; D011157:Population Dynamics; D011235:Predatory Behavior; D045483:Rivers