Natural stressors and disease risk: does the threat of predation increase amphibian susceptibility to ranavirus?
Abstract:Emerging infectious diseases have been identified as threats to biodiversity, yet our understanding of the factors contributing to host susceptibility to pathogens within natural populations remains limited. It has been proposed that species interactions within communities affect host susceptibility to pathogens, thereby contributing to disease emergence. In particular, predation risk is a common natural stressor that has been hypothesized to compromise immune function of prey through chronic stress responses possibly leading to increased susceptibility to pathogens. We examined whether predation risk experienced during the development of four larval anuran species increases susceptibility (mortality and infection) to ranaviruses, a group of viruses responsible for amphibian die-offs. Using controlled laboratory experiments, we exposed each species to a factorial combination of two virus treatments (no virus or virus) crossed with three predator-cue treatments (no predators, larval dragonflies, or adult water bugs). All four amphibian species reduced activity by 22%–48% following continuous exposure to predator cues. In addition, virus exposure significantly reduced survival by 17%–100% across all species. However, exposure to predator cues did not interact with the virus treatments to elevate mortality or viral load. Our results suggest that the expression of predator-induced plasticity in anuran larvae does not increase ranaviral disease risk.
Keywords: Anax sp; Belostoma flumineum; Hyla chrysoscelis; Lithobates clamitans; Lithobates sylvaticus; Pseudacris feriarum; disease ecology; défense inductible; emerging infectious disease; frog virus 3; inducible defense; interactions trophiques; maladie infectieuse émergente; parasite; phenotypic plasticity; plasticité phénotypique; ranavirus; trophic interactions; virus 3 de la grenouille; écologie des maladies
Document Type: Research Article
Affiliations: Center for Wildlife Health, Department of Forestry, Wildlife, and Fisheries, University of Tennessee, Knoxville, TN 37996, USA.
Publication date: July 22, 2012
- Published since 1929, this monthly journal reports on primary research contributed by respected international scientists in the broad field of zoology, including behaviour, biochemistry and physiology, developmental biology, ecology, genetics, morphology and ultrastructure, parasitology and pathology, and systematics and evolution. It also invites experts to submit review articles on topics of current interest.
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