Disentangling relationships between physiology, morphology, diet, and gut microbial diversity in American Kestrel nestlings

Gut microbiota are increasingly recognized as important drivers of host health and fitness across vertebrate taxa. Given that gut microbial composition is directly influenced by the environment, gut microbiota may also serve as an eco-physiological mechanism connecting host ecology, such as diet, and physiology. Although gut microbiota have been well-studied in mammalian systems, little is known about how gut microbial diversity and composition impact morphological and physiological development in wild birds. Here, we characterized both diet and gut microbial diversity of free-living American kestrel (Falco sparverius) nestlings throughout development to test whether gut microbial diversity predicts host morphological and physiological traits in either contemporary or time-lagged manners. Gut microbial alpha diversity on day 21 of nestling development was positively correlated with diet alpha diversity representative of the majority of nestling development (days 5–20). Gut microbial alp..., Sample Collection We monitored American kestrel (Falco sparverius) nest-boxes in Berks, Lehigh, and Schuylkill Counties, Pennsylvania, USA beginning in early May 2018 and 2019 to document occupancy, egg-laying date, and hatching as described in Cornell et al. (2021). In 2018, we sampled 12 nestlings from 4 nests, and in 2019 we sampled 32 nestlings from 10 nests (n = 44 nestlings total). On days 7, 14, and 21 after hatching (hatch day = day 0), we removed nestlings from the nest and collected morphometrics, blood samples, and fecal samples between 8:00 and 12:00 hours (following university IACUC and US Fish and Wildlife Service banding permits). Birds were sexed on day 21 from coloration of primary feathers: blue for males and brown for females (Smallwood and Bird 2020). We measured mass to the nearest 0.01 g using a digital scale. We banded nestlings with uniquely colored temporary leg bands (Darvic Wraparound 1FB, 5.5 mm, Avinet) on day 7 for identification within nests and banded wit..., We have included scripts for QIIME2 (version 2021.11) and R (version 4.2.1). See READMe for more information. Â肠道微生物群（gut microbiota）日益被证实为脊椎动物类群宿主健康与生存繁殖适合度的关键调控因子。鉴于肠道微生物组成直接受环境调控，肠道微生物群或可作为连接宿主生态（如饮食）与生理状态的生态生理机制。尽管肠道微生物群在哺乳动物体系中已得到广泛深入研究，但针对野生鸟类中肠道微生物多样性与组成如何影响其形态与生理发育的认知仍较为匮乏。本研究对自由生活的美洲红隼（Falco sparverius）雏鸟整个发育周期的饮食与肠道微生物多样性（alpha diversity）进行了表征，以此验证肠道微生物多样性是否能以即时或滞后的方式预测宿主的形态与生理性状。雏鸟发育至第21天时的肠道微生物α多样性，与代表雏鸟多数发育阶段（第5至20天）的饮食α多样性（alpha diversity）呈显著正相关。肠道微生物α……，样品采集 我们于2018年与2019年5月初开始，对美国宾夕法尼亚州伯克县、利哈伊县与斯库尔基尔县的美洲红隼（Falco sparverius）巢箱开展监测，以记录巢箱占用情况、产卵日期与孵化进程，具体方法参照Cornell等人（2021）的研究。2018年，我们从4个巢箱中采集了12只雏鸟的样本；2019年则从10个巢箱中采集了32只雏鸟的样本，总计44只雏鸟。在雏鸟孵化后的第7、14和21天（孵化当日记为第0天），我们于每日8:00至12:00将雏鸟从巢中取出，采集形态学测量指标、血液样本与粪便样本，所有操作均符合大学机构动物护理与使用委员会（IACUC）及美国鱼类和野生动物管理局的环志许可要求。研究人员于雏鸟孵化第21天根据初级飞羽的颜色进行性别鉴定：雄性飞羽呈蓝色，雌性呈棕色（Smallwood与Bird, 2020）。我们使用数字天平称量雏鸟体重，精度可达0.01 g。我们于第7天为雏鸟佩戴带有唯一标识的彩色临时脚环（Darvic Wraparound 1FB型，规格5.5 mm，Avinet品牌），以实现巢内个体识别，并佩戴了…… 本研究提供了QIIME2（版本2021.11）与R（版本4.2.1）的分析脚本，详细信息请参见README文件。