Urban living can rescue Darwin's finches from the lethal effects of invasive vampire flies
Urban living can rescue Darwin's finches from the lethal effects of invasive vampire flies
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DOI：
10.1111/gcb.17145
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发表时间：
2024-01-01
影响因子：
11.6
通讯作者：
Wegrzyn，Jill L.
中科院分区：
文献类型：
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作者：
Knutie，Sarah A.;Webster，Cynthia N.;Wegrzyn，Jill L.
人类活动改变了环境中的多种因素，对生物体可能产生积极或消极的协同效应。然而，很少有研究探讨多种人为因素（如城市化和入侵物种）对动物的因果影响以及介导这些相互作用的机制。本研究探讨了城市化对加拉帕戈斯群岛特有的达尔文雀的有害影响，入侵的鸟类吸血蝇（Philornis downsi）。我们实验性地操纵了城市和非城市地区的巢蝇丰度，然后描述了雏鸟的健康状况，雏鸟的成功，饮食和与宿主防御相关的基因表达模式。来自城市（79%）和非城市（75%）巢穴的未寄生雏鸟的羽化成功率没有显着差异。然而，寄生，非城市雏鸟失去更多的血液，更少的雏鸟存活（8%）相比，城市雏鸟（50%）。来自城市雏鸟粪便的稳定同位素值（δ 15 N）高于非城市雏鸟，表明城市雏鸟消耗更多的蛋白质。δ 15 N值与寄生虫丰度呈负相关，这表明饮食可能影响宿主防御（例如，宽容和抵抗）。与寄生的非城市雏鸟相比，寄生的城市雏鸟在与红细胞产生（耐受性）和促炎反应（先天免疫抗性）相关的途径中差异表达基因。相反，寄生的非城市雏鸟在与免疫球蛋白产生相关的途径中差异表达基因（适应性免疫抗性）。我们的研究结果表明，城市雏鸟在抵抗寄生虫的促炎反应方面投入更多，但也恢复了更多的血细胞以耐受失血。虽然非城市雏鸟正在进行适应性免疫反应，但这可能是免疫系统的最后努力，而不是对鸟类吸血蝇的有效防御，因为很少有雏鸟存活下来。
Human activity changes multiple factors in the environment, which can have positive or negative synergistic effects on organisms. However, few studies have explored the causal effects of multiple anthropogenic factors, such as urbanization and invasive species, on animals and the mechanisms that mediate these interactions. This study examines the influence of urbanization on the detrimental effect of invasive avian vampire flies (Philornis downsi) on endemic Darwin's finches in the Galápagos Islands. We experimentally manipulated nest fly abundance in urban and non‐urban locations and then characterized nestling health, fledging success, diet, and gene expression patterns related to host defense. Fledging success of non‐parasitized nestlings from urban (79%) and non‐urban (75%) nests did not differ significantly. However, parasitized, non‐urban nestlings lost more blood, and fewer nestlings survived (8%) compared to urban nestlings (50%). Stable isotopic values (δ15N) from urban nestling feces were higher than those from non‐urban nestlings, suggesting that urban nestlings are consuming more protein. δ15N values correlated negatively with parasite abundance, which suggests that diet might influence host defenses (e.g., tolerance and resistance). Parasitized, urban nestlings differentially expressed genes within pathways associated with red blood cell production (tolerance) and pro‐inflammatory response (innate immunological resistance), compared to parasitized, non‐urban nestlings. In contrast, parasitized non‐urban nestlings differentially expressed genes within pathways associated with immunoglobulin production (adaptive immunological resistance). Our results suggest that urban nestlings are investing more in pro‐inflammatory responses to resist parasites but also recovering more blood cells to tolerate blood loss. Although non‐urban nestlings are mounting an adaptive immune response, it is likely a last effort by the immune system rather than an effective defense against avian vampire flies since few nestlings survived.