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Immunity changes through ontogeny and can mediate facilitative and inhibitory interactions among co-infecting parasite species. In amphibians, most immune memory is not carried through metamorphosis, leading to variation in the complexity of immune responses across life stages. To test if the ontogeny of host immunity might drive interactions among co-infecting parasites, we simultaneously exposed Cuban treefrogs ( Osteopilus septentrionalis ) to a fungus ( Batrachochytrium dendrobaditis , Bd) and a nematode ( Aplectana hamatospicula ) at tadpole, metamorphic and post-metamorphic life stages. We measured metrics of host immunity, host health and parasite abundance. We predicted facilitative interactions between co-infecting parasites as the different immune responses hosts mount to combat these infectious are energetically challenging to mount simultaneously. We found ontogenetic differences in IgY levels and cellular immunity but no evidence that metamorphic frogs were more immunosuppressed than tadpoles. There was also little evidence that these parasites facilitated one another and no evidence that A. hamatospicula infection altered host immunity or health. However, Bd, which is known to be immunosuppressive, decreased immunity in metamorphic frogs. This made metamorphic frogs both less resistant and less tolerant of Bd infection than the other life stages. These findings indicate that changes in immunity altered host responses to parasite exposures throughout ontogeny. This article is part of the theme issue ‘Amphibian immunity: stress, disease and ecoimmunology’.
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Ontogeny drives shifts in skin bacterial communities in facultatively paedomorphic salamanders
Microbiomes are major determinants of host growth, development and survival. In amphibians, host-associated bacteria in the skin can inhibit pathogen infection, but many processes can influence the structure and composition of the community. Here we quantified the shifts in skin-associated bacteria across developmental stages in the striped newt (Notophthalmus perstriatus), a threatened salamander species with a complex life history and vulnerable to infection by the amphibian chytrid fungusBatrachochytrium dendrobatidisand ranavirus. Our analyses show that pre-metamorphic larval and paedomorphic stages share similar bacterial compositions, and that the changes in the microbiome coincided with physiological restructuring during metamorphosis. Newts undergoing metamorphosis exhibited microbiome compositions that were intermediate between paedomorphic and post-metamorphic stages, further supporting the idea that metamorphosis is a major driver of host-associated microbes in amphibians. We did not find support for infection-related disruption of the microbiome, though infection replicates were small for each respective life stage.
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- Award ID(s):
- 2011278
- PAR ID:
- 10559525
- Publisher / Repository:
- Microbiology Society
- Date Published:
- Journal Name:
- Microbiology
- Volume:
- 169
- Issue:
- 10
- ISSN:
- 1350-0872
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1099/mic.0.001399
