Wildlife Health Ghent, Department of Pathology, Bacteriology and Avian Diseases, Ghent University, Salisburylaan 133, Merelbeke, 9820, Belgium.
Department of Community Ecology, Helmholtz Centre for Environmental Research (UFZ), Theodor-Lieser-Strasse 4, Halle, 06120, Germany.
Ecol Lett. 2021 Jan;24(1):27-37. doi: 10.1111/ele.13616. Epub 2020 Oct 6.
While epizootics increasingly affect wildlife, it remains poorly understood how the environment shapes most host-pathogen systems. Here, we employ a three-step framework to study microclimate influence on ectotherm host thermal behaviour, focusing on amphibian chytridiomycosis in fire salamanders (Salamandra salamandra) infected with the fungal pathogen Batrachochytrium salamandrivorans (Bsal). Laboratory trials reveal that innate variation in thermal preference, rather than behavioural fever, can inhibit infection and facilitate salamander recovery under humidity-saturated conditions. Yet, a 3-year field study and a mesocosm experiment close to the invasive Bsal range show that microclimate constraints suppress host thermal behaviour favourable to disease control. A final mechanistic model, that estimates range-wide, year-round host body temperature relative to microclimate, suggests that these constraints are rule rather than exception. Our results demonstrate how innate host defences against epizootics may remain constrained in the wild, which predisposes to range-wide disease outbreaks and population declines.
尽管动物传染病越来越多地影响野生动物，但人们对环境如何塑造大多数宿主-病原体系统仍知之甚少。在这里，我们采用三步框架来研究微气候对变温动物宿主热行为的影响，重点研究感染真菌病原体蛙壶菌（Batrachochytrium salamandrivorans，Bsal）的火蝾螈（Salamandra salamandra）的传染性蛙病。实验室试验表明，与行为性发热相比，热偏好的先天差异可以抑制感染，并在高湿度饱和条件下促进蝾螈恢复。然而，一项为期 3 年的野外研究和一个接近蛙壶菌入侵范围的中观生态实验表明，微气候限制了有利于疾病控制的宿主热行为。最后一个机械模型估计了全年范围的宿主体温相对于微气候的情况，表明这些限制是普遍存在的，而非例外。我们的研究结果表明，宿主对传染病的先天防御在野外可能仍然受到限制，这容易导致疾病在整个范围内爆发和种群减少。
