Courtney L. Pike, Rebecca Hood-Nowotny, Barbara Kofler, Heinz Richner, Sabine Tebbich
{"title":"Nest climate and blood quality of two host species of the ectoparasitic Philornis downsi in the Galapagos Islands as factors of larval development","authors":"Courtney L. Pike, Rebecca Hood-Nowotny, Barbara Kofler, Heinz Richner, Sabine Tebbich","doi":"10.3389/fevo.2024.1398353","DOIUrl":null,"url":null,"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 δ<jats:sup>13</jats:sup>C and δ<jats:sup>15</jats:sup>N 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 δ<jats:sup>13</jats:sup>C 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. δ<jats:sup>15</jats:sup>N 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.","PeriodicalId":12367,"journal":{"name":"Frontiers in Ecology and Evolution","volume":null,"pages":null},"PeriodicalIF":2.4000,"publicationDate":"2024-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Frontiers in Ecology and Evolution","FirstCategoryId":"93","ListUrlMain":"https://doi.org/10.3389/fevo.2024.1398353","RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"ECOLOGY","Score":null,"Total":0}
引用次数: 0
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.
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.