Urbanization can influence many environmental factors that can affect the condition, immunity, and gut microbiota of birds. Over the past several decades, the Galápagos Islands of Ecuador have experienced increasing human activity, which has led to recent changes in the morphology, gut microbiota, and immunity of Darwin’s finches. However, these traits have not been characterized before the exponential growth of human population size and tourist visitation rates, i.e., before 2009. The goal of this study was to determine the effect of land use on the fecal microbiota, immune response, and body measurements of Darwin’s finches in 2008, at a time of rapidly increasing human activity on the islands. Specifically, we compared fecal microbiota (bacterial diversity, community structure and membership, and relative abundance of bacterial taxa), proxies of immunity (lysozyme activity and haptoglobin, complement antibody, and natural antibody levels), and body measurements (body mass and condition, tarsus length) across undeveloped, agricultural, and urban areas for medium ground finches (Geospiza fortis) and small ground finches (G. fuliginosa). Lysozyme activity was lower and observed bacterial species richness was higher in urban areas compared to non-urban areas across both finch species. In medium ground finches, four genera (Methylobacterium-Methylorubrum, Escherichia-Shigella, Brucella, and Citrobacter spp.) were higher in urban areas compared to undeveloped areas. In small ground finches, Paucibacter, Achromobacter, Delftia, Stenotrophomonas, and Brucella spp. had higher relative abundances in undeveloped and agricultural areas whereas the genus Cutibacterium was more abundant in finches from urban and agricultural areas than in finches from undeveloped areas. Medium ground finches were smaller in undeveloped areas compared to the other two areas, but body mass of small ground finches did not differ across areas. Our results suggest that human activity can have an impact on immune measures and gut microbiota of Darwin’s finches.
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This content will become publicly available on October 14, 2024
Effect of urbanization and parasitism on the gut microbiota of Darwin's finch nestlings
Host‐associated microbiota can be affected by factors related to environmental change, such as urbanization and invasive species. For example, urban areas often affect food availability for animals, which can change their gut microbiota. Invasive parasites can also influence microbiota through competition or indirectly through a change in the host immune response. These interacting factors can have complex effects on host fitness, but few studies have disentangled the relationship between urbanization and parasitism on an organism's gut microbiota. To address this gap in knowledge, we investigated the effects of urbanization and parasitism by the invasive avian vampire fly (
- Award ID(s):
- 1949858
- NSF-PAR ID:
- 10469106
- Publisher / Repository:
- Wiley-Blackwell
- Date Published:
- Journal Name:
- Molecular Ecology
- Volume:
- 32
- Issue:
- 22
- ISSN:
- 0962-1083
- Format(s):
- Medium: X Size: p. 6059-6069
- Size(s):
- ["p. 6059-6069"]
- Sponsoring Org:
- National Science Foundation
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Abstract 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 (
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