Ecological energetics, behavioural variation and wildlife disease

随着全球旅行和贸易影响病原体的传播，以及环境变化影响宿主的易感性，野生动物的传染病日益受到关注。人们越来越认识到，病原体可能导致物种灭绝、生物多样性丧失以及对人类公共健康和经济的影响。在北美，冬眠蝙蝠面临着一种持续不断的保护危机，这种疾病是由侵袭性真菌疾病白鼻症引起的。嗜寒的WNS病原体在蝙蝠冬眠期间感染皮肤，导致一连串的生理变化，最终导致蝙蝠过快地消耗冬季脂肪储备。至于其他增加宿主能量成本的病原体，帮助蝙蝠增加能量摄入或减少消耗的特征可能对生存至关重要。WNS病原体通过蝙蝠之间的接触传播，但也通过洞穴中受感染的底物传播。因此，在社交能力或探索性行为(即个性)方面的可重复差异可能会影响病原体暴露的风险并影响生存。我的长期目标是检验一个广泛的假设，即个人、社会群体和宿主群体之间的行为和生理差异会影响宿主-病原体动态和野生动物疾病的影响。对于这个发现基金，我的短期目标是在蝙蝠身上使用WNS来测试我长期目标中出现的三个假说：1)具有改善冬季和夏季能量平衡的生理特征的个体(高食物摄入量和脂肪储存，体温和新陈代谢周期性降低的高表达称为Torpor)在入侵后将有更高的年存活率，导致持续存在的蝙蝠种群向这些特征的表型转变；2)具有行为特征的个体在入侵后将有更高的年存活率，从而导致种群水平的行为表型转变；2)具有降低病原体暴露风险的个体(较少社交、探索性、较小的同居)将在入侵后有更高的年存活率，从而导致种群水平的行为表型变化；3)改善能量收支的摄入量和输出量的环境控制措施可以提高受病原体影响的人群的生死率。为了解决目标1和目标2，我和我的学生将增加我们的大型数据库，关于加拿大中部有标记的蝙蝠在WNS入侵前的精力和行为特征，以及WNS入侵后幸存者的数据。我们还将比较WNS敏感和抗WNS物种之间夏季家养和麻木的表达。为了达到目标3，我们将测试栖息地操作对有WNS的蝙蝠生存和繁殖的影响，这些操作可以增加能量摄入或减少能量消耗。尽管有野生动物病原体的潜在影响，但揭示宿主群体如何反应的实验数据相对较少，当野生动物疾病爆发时，也几乎没有抗击野生动物疾病爆发的工具。我的计划将阐明宿主应对病原体的进化，以及抗击WNS和其他疾病的潜在管理策略。

Infectious diseases of wildlife are an increasing concern as global travel and trade affect pathogen dispersal, and environmental change affects host susceptibility. There is growing realization that pathogens can cause species extinctions, loss of biodiversity and impacts on human public health and the economy. In North America, hibernating bats face an ongoing conservation crisis from the invasive fungal disease white-nose syndrome. The cold-loving WNS pathogen infects the skin of bats during hibernation causing a cascade of physiological changes that ultimately cause bats to expend their winter fat reserves too quickly. As for other pathogens that increase host energetic costs, traits that help bats increase energy intake or reduce expenditure could be crucial for survival. The WNS pathogen is spread by contact between bats but also from infected substrates in caves. Thus repeatable differences in sociability or explorative behaviours (i.e., personality), could affect the risk of pathogen exposure and influence survival. My long-term objective is to test the broad hypothesis that behavioural and physiological variation among individuals, social groups and populations of hosts affects host-pathogen dynamics and wildlife disease impacts. For this Discovery Grant, my short-term objectives are to use WNS in bats to test three hypotheses that emerge from my long-term goal: 1) Individuals with physiological traits that improve winter and summer energy balance (high food intake and fat storage, high expression of periodic reductions in body temperature and metabolism called torpor) will have higher annual survival after invasion resulting in a phenotypic shift toward these traits in persisting bat populations; 2) Individuals with behavioural traits that reduce risk of pathogen exposure (less sociable, explorative, smaller homerange) will have higher annual survival after invasion leading to population-level phenotypic shifts in behaviour; and 3) Environmental manipulations that improve both the intake and output sides of the energy budget can improve vital rates for pathogen-impacted populations. To address Objectives 1 and 2, my students and I will add to our large dataset on pre-WNS energetic and behavioural traits of marked bats in central Canada, with data from survivors that remain after WNS invasion. We will also compare summer homerange and torpor expression between a WNS-susceptible and WNS-resistant species. To address Objective 3 we will test the influence of habitat manipulations that could increase energy intake or reduce energy expenditure on survival and reproduction of bats with WNS. Despite potential impacts of wildlife pathogens, we have relatively few experimental data revealing how host population respond, and few tools to combat wildlife disease outbreaks when they occur. My program will shed light on the evolution of hosts in response to pathogens as well as potential management strategies to combat WNS and other diseases.