Climate change and infectious disease by the chytrid fungus Batrachochytrium dendrobatidis (Bd) are major drivers of amphibian extinctions, but the potential interactions of these two factors are not fully understood. Temperature is known to influence (1) the infectivity, pathogenicity and virulence of Bd; (2) host-parasite dynamics, especially when both hosts and parasites are ectothermic organisms exhibiting thermal sensitivities that may or may not differ; and (3) amphibian vulnerability to extinction depending on their heat tolerance, which may decrease with infection. Thus, in a global warming scenario, with rising temperatures and more frequent and extreme weather events, amphibians infected by Bd could be expected to be more vulnerable if temperatures approach their critical thermal maximum (CTmax). However, it is also possible that predicted high temperatures could clear the Bd infection, thus enhancing amphibian survival. We tested these hypotheses by measuring CTmax values of Bd-infected and Bd-free aquatic tadpoles and terrestrial toadlets/juveniles of the common midwife toad (Alytes obstetricans) and examining whether exposure of A. obstetricans individuals to peak temperatures reaching their CTmax clears them from Bd infection. We show that (1) Bd has a wide thermal tolerance range; (2) Bd is capable of altering the thermal physiology of A. obstetricans, which is stage-dependent, lowering CTmax in tadpoles but not in toadlets; and (3) Bd infection is not cleared after exposure of tadpoles or toadlets to CTmax. Living under climatic change with rising temperatures, the effect of Bd infection might tip the balance and lead some already threatened amphibian communities towards extinction.
1.CSIC, Museo Nacl Ciencias Nat, Madrid, Spain 2.Univ Basque Country, UPV EHU, Fac Sci & Technol, Dept Plant Biol & Ecol, Leioa, Spain 3.Basque Fdn Sci, Ikerbasque, Bilbao, Spain 4.Univ Autonoma Chile, Fac Arquitectura & Construcc, IEH, Unidad Cambio Climat & Medio Ambiente, Temuco, Chile 5.Univ Catolica Temuco, Nucleo Estudio Ciencias Ambientales NEA, Temuco, Chile 6.Univ Catolica Temuco, Dept Ciencias Ambientales, Fac Recursos Nat, Temuco, Chile 7.CSIC, Estn Biol Donana, Dept Evolutionary Ecol, Amer Vespucio S-N, Seville, Spain 8.Hungarian Acad Sci, Plant Protect Inst, Lendulet Evolutionary Ecol Res Grp, Ctr Agr Res, Budapest, Hungary 9.Univ Vet Med, Inst Biol, Dept Ecol, Budapest, Hungary 10.Ctr Invest Seguimiento & Evaluac, Parque Nacl Sierra Guadarrama, Rascafria, Spain 11.Oviedo Univ, Res Unit Biodivers, CSIC, UO,PA, Campus Mieres, Mieres, Spain
Recommended Citation:
Fernandez-Loras, Andres,Boyero, Luz,Correa-Araneda, Francisco,et al. Infection with Batrachochytrium dendrobatidis lowers heat tolerance of tadpole hosts and cannot be cleared by brief exposure to CTmax[J]. PLOS ONE,2019-01-01,14(4)