Male reproductive effort might be evolving in the face of devastating disease in a threatened amphibian

The devastating infectious disease chytridiomycosis has caused declines of amphibians across the globe, yet some populations are persisting and even recovering. One understudied effect of wildlife disease is changes in reproductive effort. Here we aimed to understand if disease has plastic effects on reproduction and if reproductive effort could evolve with disease endemism. We compared the effects of experimental pathogen exposure (trait plasticity) and population-level disease history (evolution in trait baseline) on reproductive effort using gametogenesis as a proxy in the declining and endangered frog Litoria verreauxii alpina. We found that unexposed males from disease-endemic populations had higher reproductive effort, which is consistent with an evolutionary response to chytridiomycosis. We also found evidence of trait plasticity, where males and females were affected differently by infection: pathogen exposed males had higher reproductive effort (larger testes), whereas females ...