Sympatric population divergence within a highly pelagic seabird species complex (Hydrobates spp.)

Abstract

Both physical and non-physical barriers can restrict gene flow among seabird populations. Understanding the relative importance of non-physical barriers, such as breeding phenology, is key to understanding seabird biodiversity. We investigated drivers of diversification in the Leach's storm-petrel species complex (Hydrobates spp.) by examining population genetic structure across its range. Variation in the mitochondrial control region and six microsatellite loci was assayed in birds sampled from breeding colonies throughout the North Atlantic and North Pacific (H. leucorhoa leucorhoa), as well as from San Benito Islands (H. l. chapmani), and two seasonal populations in Guadalupe (summer breeding H. socorroensis and winter breeding H. cheimomnestes), Mexico. Weak but significant differentiation was found between populations of H. l. leucorhoa breeding in the Atlantic versus North Pacific, as well as between H. l. chapmani and H. l. leucorhoa, and between H. socorroensis and H. cheimomnestes within Guadalupe. In contrast, strong differentiation in both mitochondrial DNA and microsatellites was found between H. leucorhoa and both H. socorroensis and H. cheimomnestes. Phylogenetic reconstruction suggested the Guadalupe seasonal breeding populations are sister taxa, at least in their mitochondrial DNA. Non-physical barriers to gene flow appear to be more important than physical barriers in driving divergence within the Leach's storm-petrel species complex. In particular, allochronic speciation may have occurred between the seasonal populations within Guadalupe. Further work should include higher resolution sequencing to confirm results, and an increased sampling effort, particularly within the California area, to fully resolve the relationship between H. l. leucorhoa and H. l. chapmani.

Complex population structure of the Atlantic puffin revealed by whole genome analyses

“…oceanography, foraging behavior, at-sea range, and phenology 14 . Detailed genomic data including thousands of loci provide new possibilities to assess levels of connectivity and gene flow between distinct breeding populations and, thus, help identify relevant conservation units for seabirds 14,15 . Indeed, a few recent publications using reduced genomic representation approaches (e.g.…”

Complex population structure of the Atlantic puffin revealed by whole genome analyses

“…Defining such units is, however, difficult for many seabirds because of their complex ecology 15 . Detailed genomic data including thousands of loci provide new possibilities to assess levels of connectivity and gene flow between distinct breeding populations and, thus, help identify relevant conservation units for seabirds 15 , 16 . Indeed, a few recent publications using reduced genomic representation approaches (e.g., RAD-seq) have reported fine-scale structure over various spatial scales 17 – 21 .…”

Seasonal migration patterns and the maintenance of evolutionary diversity in a cryptic bird radiation

“…tibetana (see below) ‐ might act as prezygotic isolation mechanisms. Speciation through allochrony, that is, temporal segregation of breeding populations as an important contributor to reproductive isolation, has been invoked in several animal groups, including birds (e.g., Bearhop et al, 2005 ; Friesen et al, 2007 ; Gómez‐Bahamón et al, 2020 ; Kimmitt et al, 2019 ; Sirkiä et al, 2018 ; Taylor et al, 2018 , 2019 ; Taylor & Friesen, 2017 ). However, other potential prezygotic isolation mechanisms such as differences in mating behaviour between R. d .…”