Disease‑associated change in an amphibian life‑history trait

Scheele, Benjamin C., Skerratt, Lee F., Hunter, David A., Banks, Sam C., Pierson, Jennifer C., Driscoll, Don A., Byrne, Philip G., and Berger, Lee (2017) Disease‑associated change in an amphibian life‑history trait. Oecologia, 2017. (In Press)

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Abstract

Emerging pathogens can drive evolutionary shifts in host life-history traits, yet this process remains poorly documented in vertebrate hosts. Amphibian chytridiomycosis, caused by infection with the fungal pathogen Batrachochytrium dendrobatidis (Bd), is the worst recorded wildlife disease and has caused the extinction of over 100 species across multiple continents. A similar number of additional species have experienced mass declines and Bd remains a major source of mortality in many populations of declined species now persisting with the pathogen. Life-history theory predicts that increased extrinsic mortality in Bd-infected populations may alter amphibian life-history traits, but this has not been examined. Here, we investigate whether population Bd status is associated with age and size at maturity by comparing long-exposed Bd-infected populations, Bd-free populations, and museum specimens collected prior to Bd emergence for the endangered Australian frog Litoria verreauxii alpina. We show that Bd-infected populations have a higher proportion of males that mature at 1 year of age, and females that mature at 2 years of age, compared to Bd-free populations. Earlier maturation was associated with reduced size at maturity in males. Consistent with life-history theory, our findings may represent an adaptive evolutionary shift towards earlier maturation in response to high Bd-induced mortality. To our knowledge, this study provides the first evidence for a post-metamorphic Bd-associated shift in an amphibian life-history trait. Given high mortality in other Bd-challenged species, we suggest that chytridiomycosis may be a substantial new selection pressure shaping life-history traits in impacted amphibian species across multiple continents.

Item ID: 49658
Item Type: Article (Refereed Research - C1)
Keywords: Batrachochytrium dendrobatidis, Chytrid fungus, maturation rates, pathogen, wildlife disease
ISSN: 1432-1939
Funders: Taronga Zoo (TZ), New South Wales Office of Environment and Heritage (NSWOEH), Australian Research Council (ARC)
Projects and Grants: TZ Conservation Grant, ARC LP110200240 and FT100100375
Date Deposited: 25 Jul 2017 02:37
FoR Codes: 07 AGRICULTURAL AND VETERINARY SCIENCES > 0707 Veterinary Sciences > 070704 Veterinary Epidemiology @ 50%
06 BIOLOGICAL SCIENCES > 0603 Evolutionary Biology > 060303 Biological Adaptation @ 50%
SEO Codes: 96 ENVIRONMENT > 9608 Flora, Fauna and Biodiversity > 960810 Mountain and High Country Flora, Fauna and Biodiversity @ 100%
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