Evolutionary ecology of host competence after a chytrid outbreak in a naive amphibian community

Abstract

Naive multi-host communities include species that may differentially maintain, transmit and amplify novel pathogens; therefore, we expect species to fill distinct roles during infectious disease emergence. Characterizing these roles in wildlife communities is challenging because most disease emergence events are unpredictable. Here, we used field-collected data to investigate how species-specific attributes influenced the degree of exposure, probability of infection, and pathogen intensity, during the emergence of the fungal pathogen Batrachochytrium dendrobatidis ( Bd ) in a highly diverse tropical amphibian community. Our findings confirmed that ecological traits commonly evaluated as correlates of decline were positively associated with infection prevalence and intensity at the species level during the outbreak. We identified key hosts that disproportionally contributed to transmission dynamics in this community and found a signature of phylogenetic history in disease responses associated with increased pathogen exposure via shared life-history traits. Our findings establish a framework that could be applied in conservation efforts to identify key species driving disease dynamics under enzootics before reintroducing amphibians back into their original communities. Reintroductions of supersensitive hosts that are unable to overcome infections will limit the success of conservation programmes by amplifying the disease at the community level. This article is part of the theme issue ‘Amphibian immunity: stress, disease and ecoimmunology’.

Playing it safe at early life stages: Balancing energy allocations to maximize fitness under seasonal pathogen dynamics

“…Hosts across taxa show variation in their physiological and immunological responses to epizootics of emerging pathogens (Genersch & Aubert 2010;Huot et al 2014;Kohl et al 2016;Longo et al 2023;Malpica et al 2006;Soler et al 2003;Webster et al 2017;Wilder et al 2011).…”

Introduction to the special issue Amphibian immunity: stress, disease and ecoimmunology

“…However, characterizing the roles of different species in wildlife communities during infectious disease emergence is challenging as these events are often unpredictable. How species-specific attributes influence exposure, probability of infection, and pathogen intensity during the fungal pathogen ( Bd ) emergence was the central question of [ 104 ] in this issue. The authors used field-collected data and found that some hosts disproportionately contributed to transmission dynamics [ 104 ].…”

“…How species-specific attributes influence exposure, probability of infection, and pathogen intensity during the fungal pathogen ( Bd ) emergence was the central question of [ 104 ] in this issue. The authors used field-collected data and found that some hosts disproportionately contributed to transmission dynamics [ 104 ]. This information is particularly important when considering reintroducing amphibians back into their original communities.…”

“…These tools can be used in wildlife and experimental conditions to manage emerging pathogens, and monitor and predict disease susceptibility in amphibian populations, helping to understand amphibian survival in a changing world. Moreover, the papers in this issue bring insights into the importance of understanding the amphibian immune response (at larval and adult stages) to the diseases to understand better the mechanisms that drive differences among populations and species [ 36 , 46 , 52 , 54 , 88 , 104 ], which could help to predict amphibian conservation strategies.…”