Similar hybrid composition among different age and sex classes in the Myrtle-Audubon's warbler hybrid zone

David Toews, Irby J. Lovette, Darren E. Irwin, Alan Brelsford

Research output: Contribution to journalArticle

Abstract

Hybrid zones provide a key natural context within which to study the barriers between incipient species. In some avian hybrid zones, there is indirect evidence of selection against hybrid offspring, yet the source of that selection is often unclear. We examined the frequency distribution of hybrids between Myrtle Warblers (Setophaga coronata coronata) and Audubon's Warblers (S. c. auduboni), using data to quantify-for the first time at a genomic scale-the composition of hybrids in this hybrid zone. We sampled birds during the breeding season and during fall migration and compared the frequencies of hybrids of different sex and age classes. Specifically, we tested for evidence of early-generation hybrids being significantly under- or over-represented in any of these classes, as would be expected if hybrids have lower or higher fitness than non-hybrids. We found that the genomic composition of birds in the hybrid zone spans the full ancestry spectrum. Across all our sampling periods, we found an excess of birds that had more Audubon's ancestry, with a stronger bias toward Audubon's ancestry in fall migrants than in breeding birds, consistent with asymmetric introgression. Notably, we did not find any differences in hybrid frequencies between juvenile and adult age classes or between males and females. Therefore, our results do not support large differences in viability between male and female hybrids or between different age classes of hybrids.

Original languageEnglish (US)
Pages (from-to)1133-1145
Number of pages13
JournalAuk
Volume135
Issue number4
DOIs
StatePublished - Oct 1 2018

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Myrtus communis
hybrid zone
gender
age class
ancestry
bird
age structure
genomics
birds
introgression
Setophaga
breeding season
viability
fitness

All Science Journal Classification (ASJC) codes

  • Ecology, Evolution, Behavior and Systematics
  • Animal Science and Zoology

Cite this

Toews, David ; Lovette, Irby J. ; Irwin, Darren E. ; Brelsford, Alan. / Similar hybrid composition among different age and sex classes in the Myrtle-Audubon's warbler hybrid zone. In: Auk. 2018 ; Vol. 135, No. 4. pp. 1133-1145.
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Similar hybrid composition among different age and sex classes in the Myrtle-Audubon's warbler hybrid zone. / Toews, David; Lovette, Irby J.; Irwin, Darren E.; Brelsford, Alan.

In: Auk, Vol. 135, No. 4, 01.10.2018, p. 1133-1145.

Research output: Contribution to journalArticle

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