Are urbanization and brood parasitism associated with differences in telomere lengths in song sparrows?

Urbanization reflects a major form of environmental change impacting wild birds globally. Whereas urban habitats may provide increased availability of water, some food items, and reduced predation levels compared to rural, they can also present novel stressors including increased light at night, ambient noise, and reduced nutrient availability. Urbanization can also alter levels of brood parasitism, with some host species experiencing elevated levels of brood parasitism in urban areas compared to rural areas. Though the demographic and behavioral consequences of urbanization and brood parasitism have received considerable attention, their consequences for cellular-level processes are less understood. Telomeres provide an opportunity to understand the cellular consequences of different environments as they are a well-established metric of biological state that can be associated with residual lifespan, disease risk, and behaviour, and are known to be sensitive to environmental conditions...., , , # Are urbanization and brood parasitism associated with differences in telomere lengths in song sparrows? **rTLDryad.masterfile.csv** The data presented here is relative telomere length, and life history data collected from adult and nestling wild song sparrows (Melospiza melodia), and how they relate to urbanization, and brood parasitism by brown-headed cowbirds (Molothrus ater). ## Description of the data and file structure Code and data for Journal of Avian Biology Submission JAV-03220 **Variables:** * plate - qPCR plate number * Age.day - Age of nestlings in days since hatch, which is indicated by day zero * Habitat - the habitat type that the individual was sample, either urban or rural * SOSP.brood.size – number of song sparrow nestlings in a nest. * Total.brood.size- Total number of nestlings in a nest, derived from adding number of song sparrows and number of brown headed cowbird nestlings in a given nest. * rTL - Relative telomere length * date - Calendar date the samp...城市化是全球范围内影响野生鸟类的主要环境变化形式之一。相较于乡村生境，城市生境可提升水源、部分食物的可获得性并降低捕食压力，但同时也会带来全新的环境胁迫因子，包括夜间光照增强、环境噪声以及营养可获得性下降。城市化还会改变巢寄生（brood parasitism）水平，部分宿主物种在城市区域的巢寄生发生率相较于乡村区域有所升高。尽管城市化与巢寄生的种群统计及行为后果已受到广泛关注，但二者对细胞水平生理过程的影响仍有待深入阐明。端粒（Telomeres）为探究不同环境的细胞层面效应提供了理想途径：作为被广泛验证的生物状态衡量指标，端粒长度与剩余寿命、疾病风险及行为特征密切相关，且已知其对环境变化极为敏感。 # 城市化与巢寄生是否与歌带鹀的端粒长度差异相关？ **rTLDryad.masterfile.csv** 本数据集包含相对端粒长度数据，以及从野生成年歌带鹀（Melospiza melodia）和雏鸟中采集的生活史数据，旨在探究这些指标与城市化以及褐头牛鹂（Molothrus ater）巢寄生的关联。 ## 数据与文件结构说明 用于《鸟类生物学杂志》（Journal of Avian Biology）投稿JAV-03220的代码与数据集 ### 变量说明： * 板号（plate）：实时荧光定量PCR（qPCR）反应板编号 * 日龄（Age.day）：雏鸟自破壳起的天数，以破壳当日为第0天 * 生境类型（Habitat）：采样个体所在的生境类型，分为城市生境与乡村生境两类 * 歌带鹀窝雏数（SOSP.brood.size）：单个鸟巢内歌带鹀雏鸟的数量 * 总窝雏数（Total.brood.size）：单个鸟巢内的总雏鸟数量，由歌带鹀雏鸟与褐头牛鹂雏鸟的数量之和计算得到 * 相对端粒长度（rTL）：相对端粒长度 * 采样日期（date）：样本采集的公历日期……