Nest climate and blood quality of two host species of the ectoparasitic Philornis downsi in the Galapagos Islands as factors of larval development

IF 2.4 3区环境科学与生态学 Q2 ECOLOGY

Frontiers in Ecology and Evolution Pub Date : 2024-08-30 DOI:10.3389/fevo.2024.1398353

Courtney L. Pike, Rebecca Hood-Nowotny, Barbara Kofler, Heinz Richner, Sabine Tebbich

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Abstract

The avian vampire fly is an invasive species on the Galapagos Islands, where its hematophagous larvae utilize nestling birds as hosts. It poses a serious threat to populations and species of Darwin finches and other avian species. Prior studies suggest that the avian vampire fly larvae develop more rapidly in nests of small tree finches compared to sympatric green warbler finch nests. Here we investigate factors that may differentially influence larval growth in the two host species, including nest microclimate and nestling diet. We collected nest base temperature and humidity data as proxies for nest microclimate. As indicators of dietary composition and quality, we measured stable isotope δ13C and δ15N composition of nestling blood, used the C:N ratios as an indicator of relative protein content, and assessed the amino acid composition of the blood. The hematophagous larvae living off nestling blood were analyzed for the same parameters except amino acid composition. The effect of nest base humidity on nest base temperature significantly depended on bird species: at low humidity levels nest base temperature was higher in the small tree finch, and declined in both species as nest base humidity increased, which suggests higher stable heat capacity of small tree finch nests. The effect of age group based on the predicted onset of thermoregulation was marginally significant. Nest base temperatures were significantly higher in small tree finch nests during the predicted female brooding period before fully effective thermoregulation. Stable isotope δ13C levels were significantly higher in the blood of small tree finch nestlings compared to warbler finch nestlings, suggesting a difference in nestling food composition and source, while. δ15N levels were similar. The C:N ratios and amino acid composition of nestling blood were not significantly different between the two species, suggesting similar dietary quality. Thus, the faster development of larvae in small tree finch nests may be due to higher nest base temperatures during the early nestling phase rather than host blood quality parameters.

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加拉帕戈斯群岛两种外寄生虫 Philornis downsi 宿主的巢穴气候和血液质量是幼虫发育的因素

禽吸血蝇是加拉帕戈斯群岛的入侵物种，它的噬血幼虫以雏鸟为宿主。它对达尔文雀和其他鸟类的种群和物种构成严重威胁。先前的研究表明，与同域的绿莺雀巢相比，吸血蝇幼虫在小树雀巢中发育得更快。在此，我们研究了可能对两种寄主物种的幼虫生长产生不同影响的因素，包括巢穴微气候和雏鸟饮食。我们收集了巢基温度和湿度数据，作为巢穴微气候的代用指标。作为食物组成和质量的指标，我们测量了雏鸟血液中的稳定同位素δ13C和δ15N组成，用C:N比值作为相对蛋白质含量的指标，并评估了血液中的氨基酸组成。对以雏鸟血液为生的食血幼虫进行了除氨基酸组成外的相同参数分析。巢基湿度对巢基温度的影响在很大程度上取决于鸟类种类：在低湿度水平下，小树雀的巢基温度较高，而随着巢基湿度的增加，两种鸟类的巢基温度都有所下降，这表明小树雀巢穴的稳定热容量较高。根据预测的体温调节开始时间，年龄组的影响略微显著。在预测的雌鸟育雏期，小树雀的巢底温度明显高于完全有效的体温调节期。与莺雀雏鸟相比，小树雀雏鸟血液中的稳定同位素δ13C水平明显更高，这表明雏鸟的食物组成和来源不同，而莺雀雏鸟血液中的稳定同位素δ15N水平与小树雀雏鸟血液中的稳定同位素δ13C水平相似。δ15N的含量则相似。雏鸟血液中的C:N比和氨基酸组成在两个物种之间没有显著差异，表明食物质量相似。因此，小树雀巢中幼虫发育较快的原因可能是雏鸟早期巢底温度较高，而不是寄主血液质量参数。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Frontiers in Ecology and Evolution Environmental Science-Ecology

CiteScore

4.00

自引率

6.70%

发文量

1143

审稿时长

12 weeks

期刊介绍： Frontiers in Ecology and Evolution publishes rigorously peer-reviewed research across fundamental and applied sciences, to provide ecological and evolutionary insights into our natural and anthropogenic world, and how it should best be managed. Field Chief Editor Mark A. Elgar at the University of Melbourne is supported by an outstanding Editorial Board of international researchers. This multidisciplinary open-access journal is at the forefront of disseminating and communicating scientific knowledge and impactful discoveries to researchers, academics and the public worldwide. Eminent biologist and theist Theodosius Dobzhansky’s astute observation that “Nothing in biology makes sense except in the light of evolution” has arguably even broader relevance now than when it was first penned in The American Biology Teacher in 1973. One could similarly argue that not much in evolution makes sense without recourse to ecological concepts: understanding diversity — from microbial adaptations to species assemblages — requires insights from both ecological and evolutionary disciplines. Nowadays, technological developments from other fields allow us to address unprecedented ecological and evolutionary questions of astonishing detail, impressive breadth and compelling inference. The specialty sections of Frontiers in Ecology and Evolution will publish, under a single platform, contemporary, rigorous research, reviews, opinions, and commentaries that cover the spectrum of ecological and evolutionary inquiry, both fundamental and applied. Articles are peer-reviewed according to the Frontiers review guidelines, which evaluate manuscripts on objective editorial criteria. Through this unique, Frontiers platform for open-access publishing and research networking, Frontiers in Ecology and Evolution aims to provide colleagues and the broader community with ecological and evolutionary insights into our natural and anthropogenic world, and how it might best be managed.