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IntroductionThe long-distance, seasonal migrations of birds make them an effective ecological bridge for the movement of ticks. The introduction of exotic tick species to new geographical regions can cause the emergence of novel tick-borne pathogens. This study examined the prevalence of exotic tick species parasitizing migratory songbirds at stopover sites along the northern Gulf of Mexico using the mitochondrial 12S rRNA gene. MethodsOverall, 421 individual ticks in the generaAmblyomma,Haemaphysalis, andIxodeswere recorded from 28 songbird species, of whichAmblyommaandAmblyomma longirostrewere the most abundant tick genera and species, respectively. A high throughput 16S ribosomal RNA sequencing approach characterized the microbial communities and identified pathogenic microbes in all tick samples. Results and discussionMicrobial profiles showed that Proteobacteria was the most abundant phylum. The most abundant pathogens wereRickettsiaand endosymbiontFrancisella,Candidatus Midichloria, andSpiroplasma. Permutation multivariate analysis of variance revealed that the relative abundance ofFrancisellaandRickettsiadrives microbial patterns across the tick genera. We also noted a higher percentage of positive correlations in microbe-microbe interactions among members of the microbial communities. Network analysis suggested a negative correlation between a)FrancisellaandRickettsiaand, b)FrancisellaandCutibacterium. Lastly, mapping the distributions of bird species parasitized during spring migrations highlighted geographic hotspots where migratory songbirds could disperse ticks and their pathogens at stopover sites or upon arrival to their breeding grounds, the latter showing mean dispersal distances from 421–5003 kilometers. These findings spotlight the potential role of migratory birds in the epidemiology of tick-borne pathogens.
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This content will become publicly available on December 1, 2025
Wallace’s line structures seagrass microbiota and is a potential barrier to the dispersal of marine bacteria
Abstract BackgroundThe processes that shape microbial biogeography are not well understood, and concepts that apply to macroorganisms, like dispersal barriers, may not affect microorganisms in the same predictable ways. To better understand how known macro-scale biogeographic processes can be applied at micro-scales,we examined seagrass associated microbiota on either side of Wallace’s line to determine the influence of this cryptic dispersal boundary on the community structure of microorganisms. Communities were examined from twelve locations throughout Indonesia on either side of this theoretical line. ResultsWe found significant differences in microbial community structure on either side of this boundary (R2 = 0.09;P = 0.001), and identified seven microbial genera as differentially abundant on either side of the line, six of these were more abundant in the West, with the other more strongly associated with the East. Genera found to be differentially abundant had significantly smaller minimum cell dimensions (GLM: t923 = 59.50,P < 0.001) than the overall community. ConclusionDespite the assumed excellent dispersal ability of microbes, we were able to detect significant differences in community structure on either side of this cryptic biogeographic boundary. Samples from the two closest islands on opposite sides of the line, Bali and Komodo, were more different from each other than either was to its most distant island on the same side. We suggest that limited dispersal across this barrier coupled with habitat differences are primarily responsible for the patterns observed. The cryptic processes that drive macroorganism community divergence across this region may also play a role in the bigeographic patterns of microbiota.
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- Award ID(s):
- 1833880
- PAR ID:
- 10591646
- Publisher / Repository:
- Springer Nature
- Date Published:
- Journal Name:
- Environmental Microbiome
- Volume:
- 19
- Issue:
- 1
- ISSN:
- 2524-6372
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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