Population genetics of an island invasion by Japanese Bush-Warblers in Hawaii, USA

Foster, Jeffrey T.; Walker, Faith M.; Rannals, Brandy D.; Sanchez, Daniel E.

doi:10.1642/auk-17-120.1

Cited by 4 publications

(4 citation statements)

References 40 publications

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“…Compared to the mainland, effective population sizes were lower on average among island populations, which is consistent with other island-mainland bird comparisons (Leroy et al, 2021). Our estimates of within-population genetic variation were similar to estimates found in other studies of island bird species (Foster et al, 2018;Rutledge et al, 2017), yet were reduced in comparison to estimates of N e in island birds using whole-genome resequencing data (Leroy et al, 2021). However, our N e estimates were relatively high compared to other species found on the Channels Islands, such as the Channel Islands fox, which inhabits the northern Channel Islands as well (Funk et al, 2016) and island fence lizards (Sceloporus occidentalis becki) on Santa Cruz Island (Trumbo et al, 2021).…”

Section: Neutral Processes Interact To Maintain Divergencesupporting

confidence: 90%

Adaptive divergence in bill morphology and other thermoregulatory traits is facilitated by restricted gene flow in song sparrows on the California Channel Islands

et al. 2021

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Disentangling the effects of neutral and adaptive processes in maintaining phenotypic variation across environmental gradients is challenging in natural populations.Song sparrows (Melospiza melodia) on the California Channel Islands occupy a pronounced east-west climate gradient within a small spatial scale, providing a unique opportunity to examine the interaction of genetic isolation (reduced gene flow) and the environment (selection) in driving variation. We used reduced representation genomic libraries to infer the role of neutral processes (drift and restricted gene flow) and divergent selection in driving variation in thermoregulatory traits with an emphasis on the mechanisms that maintain bill divergence among islands. Analyses of 22,029 neutral SNPs confirm distinct population structure by island with restricted gene flow and relatively large effective population sizes, suggesting bill differences are probably not a product of genetic drift. Instead, we found strong support for local adaptation using 3294 SNPs in differentiation-based and environmental association analyses coupled with genome-wide association tests. Specifically, we identified several putatively adaptive and candidate loci in or near genes involved in bill development pathways (e.g., BMP, CaM, Wnt), confirming the highly complex and polygenic architecture underlying bill morphology. Furthermore, we found divergence in genes associated with other thermoregulatory traits (i.e., feather structure, plumage colour, and physiology). Collectively, these results suggest strong divergent selection across an island archipelago results in genomic changes in a suite of traits associated with climate adaptation over small spatial scales. Future research should move beyond studying univariate traits to better understand multidimensional responses to complex environmental conditions.

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Section: Neutral Processes Interact To Maintain Divergencesupporting

confidence: 90%

Adaptive divergence in bill morphology and other thermoregulatory traits is facilitated by restricted gene flow in song sparrows on the California Channel Islands

et al. 2021

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“…The Hawaiian archipelago presents a unique opportunity to examine rapid morphological change because of the extremely high number and prevalence of nonnative species and the extinction of native species (Vitousek et al 1997;Foster 2009). In fact, recent work has found that bird species introduced to the main Hawaiian Islands showed significant morphological (Mathys and Lockwood 2011;Valentin et al 2018) and genetic (Foster et al 2018;Valentin et al 2018) divergence among the main Hawaiian Islands. However, these previous studies focused on only a single species or differentiation among the Hawaiian Islands.…”

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confidence: 99%

Rapid morphological change of nonnative frugivores on the Hawaiian island of O'ahu*

Gleditsch

Sperry

2019

Evolution

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Novel ecosystems have become widespread created, in part, by the global spread of species. The nonnative species in these environments can be under intense evolutionary pressures that cause rapid morphological change, which can then influence species interactions. In Hawaii, much of the native frugivore community is extinct, replaced by nonnative bird species. Here, we determined if the passerine species of the nonnative frugivore community on O'ahu have morphologically diverged from their native ranges. We compared a variety of traits, all important for frugivory, between museum specimens from the species’ native ranges to wild individuals from O'ahu. All four species tested exhibited significant divergence ranging in magnitude from 2.3% to 13.0% difference in at least two traits. Using a method developed from quantitative genetics, we found evidence that a mixture of nonadaptive and adaptive processes worked in concert to create the observed patterns of divergence. Our results suggest that rapid morphological change is occurring and, based on the traits measured, that these changes may influence seed dispersal effectiveness. As these species are largely responsible for seed dispersal on the island, the rapid morphological change of these species can influence the stability and maintenance of plant communities on O'ahu.

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“…Thus, the colonization history of H. d. diphone is short relative to the history of the islands and is likely due to the result of accidental long‐distance dispersal event. The feasibility of this hypothesis is supported by the individual dispersal behaviour of this species, as it has naturally spread from the Oahu island to the other main Hawaii islands over the period from the 1940s to the late 1990s (Foster et al., 2018). Together with founder effect as well as restricted distribution range and the limited carrying capacity of island habitats, it is likely that the nominate subspecies has a relatively small population size.…”

Section: Discussionmentioning

confidence: 99%

“…In addition, Horornis diphone was introduced to the island of Oahu between 1929 and 1941 (Pyle & Pyle, 2017), and subsequently naturally colonized to other islands in the Hawaiian Islands. However, the exact origins of the Hawaiian populations are still a subject of debate (Foster et al., 2018). The complex is variously treated as a single species (Dickinson, 2003; Watson et al., 1986) or as two species (Clements et al., 2023; del Hoyo & Collar, 2016; Dickinson & Christidis, 2014; Gill et al., 2023).…”

Section: Introductionmentioning

confidence: 99%

Integrative taxonomy of an East Asian songbird indicates rapid dwarfism after island colonization

Wei,

Peng,

Zhang

et al. 2024

Zoologica Scripta

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Animals that colonize islands often undergo significant evolutionary changes in comparison with their continental counterparts as a response to specific island conditions. The pace of such changes can be relatively fast, which poses challenges in the evaluation of the taxonomic status of island taxa. The Japanese and Manchurian Bush Warbler species complex (Horornis diphone–canturians), which breeds in East Asia and the Japanese Archipelago, is such an avian example. This species complex exhibits significant morphological differentiation between different taxa, and the taxonomic status and phylogenetic relationships within the complex are debated. Here, we updated the taxonomy of this species complex and shed insight on its evolutionary history using multi‐locus phylogeographic and acoustic analyses. Our results support the conventional treatment of the two continental taxa borealis and canturians as subspecies of H. canturians, contrary to some recent proposals that they are affiliated to H. diphone. We also document a reduction in body size, that is dwarfism, and vocal divergence in the nominate subspecies H. d. diphone, which is endemic to the remote and isolated Ogasawara Islands. These changes may have happened following colonization of these islands, which was estimated to have taken place approximately 0.2 million years ago. Although H. d. diphone is clearly distinctive and deserves recognition as an evolutionarily significant unit, H. d. diphone and other H. diphone samples were not reciprocally monophyletic. Because of this lack of reciprocal monophyly and a relatively recent divergence time, we advocate maintaining its current subspecies status. We also detected reduced genetic diversity, measured as heterozygosity, in H. d. diphone. We suggest that conservation efforts in the Ogasawara Islands should prioritize the protection of this endemic subspecies. Collectively, our findings suggest that the separation between the populations on the East Asian continent and the Japanese Archipelago, followed by colonization of remote oceanic islands through long‐distance dispersal, underlie rapid phenotypic and genetic diversification of the Horornis diphone–canturians species complex.

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Population genetics of an island invasion by Japanese Bush-Warblers in Hawaii, USA

Cited by 4 publications

References 40 publications

Adaptive divergence in bill morphology and other thermoregulatory traits is facilitated by restricted gene flow in song sparrows on the California Channel Islands

Adaptive divergence in bill morphology and other thermoregulatory traits is facilitated by restricted gene flow in song sparrows on the California Channel Islands

Rapid morphological change of nonnative frugivores on the Hawaiian island of O'ahu*

Integrative taxonomy of an East Asian songbird indicates rapid dwarfism after island colonization

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