Size-asymmetric competition among snails disrupts production of human-infectious Schistosoma mansoni cercariae

• Type of Material: Article
• Authors: David J. Civitello, Emory University; Rachel B. Hartman, Emory University
• Language: English
• Date: 2021-07-01
• Publisher: Ecological Society of America
• Publication Version: Final Published Version
• Copyright Statement: ©2021 by the Ecological Society of America
• Final Published Version (URL): http://dx.doi.org/10.1002/ecy.3383
• Title of Journal or Parent Work: Ecology
• Volume: 102
• Issue: 7
• Start Page: e03383
• End Page: e03383
• Grant/Funding Information: DJC was supported by NIH 1R01 AI150774-01. The Schistosomiasis Resource Center provided hosts and parasites for these experiments.
• Keywords: Biomphalaria; resource competition; Animals; parasitism; Host-Parasite Interactions; Ecosystem; parasite production; Snails; Parasites; energy budget; Schistosoma mansoni; Humans; asymmetric competition; reproduction
• Research Categories: Biology, Parasitology

Abstract

Parasites can harm hosts and influence populations, communities, and ecosystems. However, parasites are reciprocally affected by population- and community-level dynamics. Understanding feedbacks between infection dynamics and larger-scale epidemiological and ecological processes could improve predictions and reveal novel control methods. We evaluated how exploitative resource competition among hosts, a fundamental aspect of population biology, influences within-host infection dynamics of the widespread human parasite Schistosoma mansoni in its intermediate host, Biomphalaria glabrata. We added size-dependent consumption of shared resources to a parameterized bioenergetics model to predict a priori the growth, parasite production, and survival of an infected focal host coexisting with an uninfected conspecific competitor in an experiment that varied competitor size. The model quantitatively anticipated that competitors disrupt growth and parasite production and that these effects increase with competitor size. Fitting the model to these data improved its match to host survivorship. Thus, resource competition alters infection dynamics, there are strong size asymmetries in these effects, and size-asymmetric resource competition effects on infection dynamics can be accurately predicted by bioenergetics theory. More broadly, this framework can assess parasite transmission and control in other contexts, such as in resource competitive host communities, or in response to eutrophication, food supplementation, or culling.