Microbial communities of salmon resource subsidies and associated necrophagous consumers during decomposition: Potential of cross-ecosystem microbial dispersal
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© 2019 Elsevier Inc. Ephemeral resource subsidies affect ecosystems at both short- and long-term temporal scales. One such resource is carrion, which varies in size and nutrient composition. Salmon of the Pacific Northwest have an anadromous life cycle resulting in immatures feeding and developing in vast oceanic expanses and adults returning to freshwater streams for spawning and eventual death, leaving large numbers of carcasses to decompose. Nutrients from these carcasses act as subsidies for both aquatic and terrestrial communities. However, what is less understood is the fate of microbial communities of the salmon upon death and then decomposition in watershed ecosystems. We evaluated the microbiomes of salmon carcasses and how they changed in conjunction with associated necrophagous larval blow fly consumers (Diptera: Calliphoridae). We determined microbes were shared among the carcass resource, internal communities of blow fly larvae, and excretions and secretions from blow fly larval aggregates. Larval feeding also represented a possible filtering effect on some microbial taxa from the collective community due to the observed decrease in microbial richness and diversity during larval growth and development. These results suggest some carcass resource microbes are not detected in the primary insect consumers during feeding, assimilation, and egestion. Ultimately, taxa remaining with larvae can potentially be dispersed into an ecosystem by adult flies. Our findings support a more general hypothesis of the potential of microbial transfer among ecosystems via salmon necrobiome food webs. Additional controlled field studies are needed to test and identify the ubiquity and mechanism of these potential bottom-up trophic dynamics.
author list (cited authors)
Pechal, J. L., Crippen, T. L., Cammack, J. A., Tomberlin, J. K., & Benbow, M. E.