Infection-nutrition feedbacks: fat supports pathogen clearance but pathogens reduce fat in a wild mammal

Though far less obvious than direct effects (clinical disease or mortality), the indirect influences of pathogens are difficult to estimate but may hold fitness consequences. Here, we disentangle the directional relationships between infection and energetic reserves, evaluating the hypotheses that energetic reserves influence infection status of the host and that infection elicits costs to energetic reserves. Using repeated measures of fat reserves and infection status in individual bighorn sheep (Ovis canadensis) in the Greater Yellowstone Ecosystem, we documented that fat influenced ability to clear pathogens (Mycoplasma ovipneumoniae) and infection with respiratory pathogens was costly to fat reserves. Costs of infection approached, and in some instances exceeded, costs of rearing offspring to independence in terms of reductions to fat reserves. Fat influenced probability of clearing pathogens, pregnancy, and over-winter survival; from an energetic perspective, an animal could surviv..., We used repeated measures of infection status and energetic reserves in female bighorn sheep from three populations in the Greater Yellowstone Ecosystem, USA that are geographically adjacent: the Whiskey Mountain population in the Wind River Range (43.4364,47 -109.551299); the Jackson population in the Gros Ventre Range (43.573926, -110.586624); and the Upper Shoshone population in the Absaroka Range (44.420117, -109.714750). We captured adult (4+ years old) females using helicopter net-gunning and chemical immobilization. Each subsequent March and December until March 2021, we recaptured previously collared females and captured new animals to maintain sample sizes. Each animal was assigned a unique identification number. All capture and handling protocols were approved by an independent Institutional Animal Care and Use Committee at the University of Wyoming (Protocol #20180305KM00296-03).
At each capture, we estimated ingesta-free body fat (IFBFat, hereafter, fat) using a combination ..., , # Energetic costs of infection in bighorn sheep

Captured data from female bighorn sheep in northwest Wyoming 2015-2021.

## Description of the data and file structure

All raw data, other than spatial data used to obtain snow depth values, is in energeticcostsdata_20240514.csv. occupancydata_20240514.csv has the data formatted for use in an occupancy model in unmarked. The data is also pseudoreplicated (10 secondary periods created for each primary period) to allow for a fixed detection probability. Survival and pregnancy data are included in survivaldata.csv and pregnancydata.csv, respectively. We were not able to catch all sheep at each capture event, and thus some animals are missing data for certain events, indicated by NA.

Columns in energeticcostsdata_20240515.csv-
IFBF: ingesta-free body fat (percent)
Herd: population that the individual is a part of
Month: month of capture
Year: year of capture
Age: estimated age (years)
M.ovi: test result for Mycoplasma ovipneumoniae, 1 indic...

尽管与病原体的直接效应（临床疾病或死亡）相比，其间接影响远不那么直观，但这类间接影响难以量化，却可能对宿主的适合度产生重要影响。本研究厘清了感染与能量储备之间的方向性关联，验证了两项假说：其一，宿主的能量储备会影响其感染状态；其二，感染会对宿主的能量储备造成消耗。本研究针对大黄石生态系统（Greater Yellowstone Ecosystem）中的个体大角羊（Ovis canadensis）开展脂肪储备与感染状态的重复测量，结果显示，脂肪储备会影响宿主清除病原体（绵羊肺炎支原体（Mycoplasma ovipneumoniae））的能力，而呼吸道病原体感染会造成宿主脂肪储备的消耗。就脂肪储备的减少量而言，感染带来的消耗接近甚至在部分情况下超过了将幼崽抚育至独立所需的能量成本。脂肪储备会影响宿主清除病原体、受孕以及越冬存活的概率；从能量视角来看，个体可存活……

本研究对美国大黄石生态系统（Greater Yellowstone Ecosystem）内三个地理毗邻的大角羊雌性种群的感染状态与能量储备开展重复测量：分别为风河山系的威士忌山种群（43.4364, 47 -109.551299）、格罗旺特雷山系的杰克逊种群（43.573926, -110.586624）以及阿布萨罗卡山系的上肖肖尼种群（44.420117, -109.714750）。研究人员采用直升机网枪诱捕结合化学保定的方式捕获成年（4岁及以上）雌性大角羊。在2021年3月之前，我们于每年3月和12月对佩戴项圈的个体进行重捕，并捕获新个体以维持样本量。每只个体均被分配唯一识别编号。所有捕获与处理流程均经怀俄明大学独立动物护理与使用委员会（Institutional Animal Care and Use Committee）审批（协议编号：20180305KM00296-03）。

每次捕获时，我们结合……方法估算个体的无食糜体脂（ingesta-free body fat，后文简称体脂）。

# 大角羊感染的能量成本
本数据集涵盖2015-2021年于怀俄明州西北部捕获的雌性大角羊相关数据。

## 数据与文件结构说明
除用于获取雪深数据的空间数据外，所有原始数据均存储于energeticcostsdata_20240514.csv文件中。occupancydata_20240514.csv文件包含适配unmarked包的占用模型的格式化数据。本数据集采用伪重复设计（每个主周期创建10个次级周期），以实现固定检测概率。存活数据与受孕数据分别存储于survivaldata.csv与pregnancydata.csv文件中。由于每次捕获无法覆盖所有个体，部分个体在部分采样事件中存在数据缺失，以NA标识。

energeticcostsdata_20240515.csv文件包含以下字段：
IFBF：无食糜体脂（百分比）
Herd：个体所属种群
Month：捕获月份
Year：捕获年份
Age：估算年龄（单位：年）
M.ovi：绵羊肺炎支原体（Mycoplasma ovipneumoniae）检测结果，1代表……