Implications for evolutionary trends from the pairing frequencies among golden‐winged and blue‐winged warblers and their hybrids

Abstract

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Extensive historical and contemporary hybridization suggests premating isolation in Vermivora warblers is not strong: A reply to Confer et al.

“…Fieldwork on these birds is challenging, but a number of research teams have monitored pairs and examined nesting success under natural conditions. Confer et al (2020) aggregate these field data from multiple studies to present an analysis of social pairing patterns in Vermivora, with the stated goal of providing greater insights into the extent of reproductive isolation in areas of breeding sympatry.…”

“…We structure our critique in three parts and conclude with a more nuanced and comprehensive interpretation of hybridization and reproductive isolation in Vermivora warblers. Confer et al (2020) focus on "primary hybridization," which they describe as the mating of "genetically pure" V. chrysoptera and V. cyanoptera. In this system, several classes of hybrids have plumage characteristics distinct from both parental types and have traditionally been named (e.g., "Brewster's warbler" is a hybrid phenotype long associated with typical first-generation [F 1 ] hybrids).…”

“…nity is very high in Vermivora and is likely facilitating hybridization, yet was not considered by Confer et al (2020), and we suggest this will have a substantial influence on the interpretation of reproductive isolation in the system; and…”

“…(Ecology and Evolution, 10, 2020). Confer et al (2020) aggregate data from multiple studies of social pairing between Vermivora chrysoptera and V. cyanoptera, two wood warblers in the family Parulidae that hybridize extensively where they co-occur. From analysis of these data, they conclude there is near-complete reproductive isolation between these two species.…”

Population Transcriptomics Reveals Gene Flow and Introgression Between Two Non-sister Alpine Gentians

“…Hybridization and the resulting introgression can potentially blur species boundaries, and may drive rare species to extinction through genetic swamping (Huxel, 1999;Todesco et al, 2016;Ma et al, 2019). Such hybridization and introgression primarily occur between closely related species, especially for lineages that have not yet evolved complete reproductive isolation (Confer et al, 2020). For example, hybridization and introgression have been observed between two subspecies that have been diverging in response to ecological selection (Anadón et al, 2015) and between two allopatric sibling species resulted from their secondary contact caused by geographic range expansion (Zamudio and Savage, 2003).…”