Hybridization and Back-Crossing in Giant Petrels (Macronectes giganteus and M. halli) at Bird Island, South Georgia, and a Summary of Hybridization in Seabirds

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dc.contributor.authorBrown, Ruth Men_ZA
dc.contributor.authorTechow, N M S Mareileen_ZA
dc.contributor.authorWood, Andrew Gen_ZA
dc.contributor.authorPhillips, Richard Aen_ZA
dc.date.accessioned2015-11-11T14:28:54Z
dc.date.available2015-11-11T14:28:54Z
dc.date.issued2015en_ZA
dc.description.abstractHybridization in natural populations provides an opportunity to study the evolutionary processes that shape divergence and genetic isolation of species. The emergence of pre-mating barriers is often the precursor to complete reproductive isolation. However, in recently diverged species, pre-mating barriers may be incomplete, leading to hybridization between seemingly distinct taxa. Here we report results of a long-term study at Bird Island, South Georgia, of the extent of hybridization, mate fidelity, timing of breeding and breeding success in mixed and conspecific pairs of the sibling species, Macronectes halli (northern giant petrel) and M . giganteus (southern giant petrel). The proportion of mixed-species pairs varied annually from 0.4-2.4% (mean of 1.5%), and showed no linear trend with time. Mean laying date in mixed-species pairs tended to be later than in northern giant petrel, and always earlier than in southern giant petrel pairs, and their breeding success (15.6%) was lower than that of conspecific pairs. By comparison, mixed-species pairs at both Marion and Macquarie islands always failed before hatching. Histories of birds in mixed-species pairs at Bird Island were variable; some bred previously or subsequently with a conspecific partner, others subsequently with a different allospecific partner, and some mixed-species pairs remained together for multiple seasons. We also report the first verified back-crossing of a hybrid giant petrel with a female northern giant petrel. We discuss the potential causes and evolutionary consequences of hybridization and back-crossing in giant petrels and summarize the incidence of back-crossing in other seabird species.en_ZA
dc.identifier.apacitationBrown, R. M., Techow, N. M. S. M., Wood, A. G., & Phillips, R. A. (2015). Hybridization and Back-Crossing in Giant Petrels (Macronectes giganteus and M. halli) at Bird Island, South Georgia, and a Summary of Hybridization in Seabirds. <i>PLoS One</i>, http://hdl.handle.net/11427/14934en_ZA
dc.identifier.chicagocitationBrown, Ruth M, N M S Mareile Techow, Andrew G Wood, and Richard A Phillips "Hybridization and Back-Crossing in Giant Petrels (Macronectes giganteus and M. halli) at Bird Island, South Georgia, and a Summary of Hybridization in Seabirds." <i>PLoS One</i> (2015) http://hdl.handle.net/11427/14934en_ZA
dc.identifier.citationBrown, R. M., Techow, M. S., Wood, A. G., & Phillips, R. A. (2015). Hybridization and Back-Crossing in Giant Petrels (Macronectes giganteus and M. halli) at Bird Island, South Georgia, and a Summary of Hybridization in Seabirds. PLoS One, 10(3). doi:10.1371/journal.pone.0121688en_ZA
dc.identifier.ris TY - Journal Article AU - Brown, Ruth M AU - Techow, N M S Mareile AU - Wood, Andrew G AU - Phillips, Richard A AB - Hybridization in natural populations provides an opportunity to study the evolutionary processes that shape divergence and genetic isolation of species. The emergence of pre-mating barriers is often the precursor to complete reproductive isolation. However, in recently diverged species, pre-mating barriers may be incomplete, leading to hybridization between seemingly distinct taxa. Here we report results of a long-term study at Bird Island, South Georgia, of the extent of hybridization, mate fidelity, timing of breeding and breeding success in mixed and conspecific pairs of the sibling species, Macronectes halli (northern giant petrel) and M . giganteus (southern giant petrel). The proportion of mixed-species pairs varied annually from 0.4-2.4% (mean of 1.5%), and showed no linear trend with time. Mean laying date in mixed-species pairs tended to be later than in northern giant petrel, and always earlier than in southern giant petrel pairs, and their breeding success (15.6%) was lower than that of conspecific pairs. By comparison, mixed-species pairs at both Marion and Macquarie islands always failed before hatching. Histories of birds in mixed-species pairs at Bird Island were variable; some bred previously or subsequently with a conspecific partner, others subsequently with a different allospecific partner, and some mixed-species pairs remained together for multiple seasons. We also report the first verified back-crossing of a hybrid giant petrel with a female northern giant petrel. We discuss the potential causes and evolutionary consequences of hybridization and back-crossing in giant petrels and summarize the incidence of back-crossing in other seabird species. DA - 2015 DB - OpenUCT DO - 10.1371/journal.pone.0121688 DP - University of Cape Town J1 - PLoS One LK - https://open.uct.ac.za PB - University of Cape Town PY - 2015 T1 - Hybridization and Back-Crossing in Giant Petrels (Macronectes giganteus and M. halli) at Bird Island, South Georgia, and a Summary of Hybridization in Seabirds TI - Hybridization and Back-Crossing in Giant Petrels (Macronectes giganteus and M. halli) at Bird Island, South Georgia, and a Summary of Hybridization in Seabirds UR - http://hdl.handle.net/11427/14934 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/14934
dc.identifier.urihttp://dx.doi.org/10.1371/journal.pone.0121688
dc.identifier.vancouvercitationBrown RM, Techow NMSM, Wood AG, Phillips RA. Hybridization and Back-Crossing in Giant Petrels (Macronectes giganteus and M. halli) at Bird Island, South Georgia, and a Summary of Hybridization in Seabirds. PLoS One. 2015; http://hdl.handle.net/11427/14934.en_ZA
dc.language.isoengen_ZA
dc.publisherPublic Library of Scienceen_ZA
dc.publisher.departmentPercy FitzPatrick Institute of African Ornithologyen_ZA
dc.publisher.facultyFaculty of Scienceen_ZA
dc.publisher.institutionUniversity of Cape Town
dc.rightsThis is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.en_ZA
dc.rights.holder© 2015 Brown et alen_ZA
dc.rights.urihttp://creativecommons.org/licenses/by/4.0en_ZA
dc.sourcePLoS Oneen_ZA
dc.source.urihttp://journals.plos.org/plosoneen_ZA
dc.subject.otherPetrelsen_ZA
dc.subject.otherHybridizationen_ZA
dc.subject.otherMitochondrial DNAen_ZA
dc.subject.otherPopulation geneticsen_ZA
dc.titleHybridization and Back-Crossing in Giant Petrels (Macronectes giganteus and M. halli) at Bird Island, South Georgia, and a Summary of Hybridization in Seabirdsen_ZA
dc.typeJournal Articleen_ZA
uct.type.filetypeText
uct.type.filetypeImage
uct.type.publicationResearchen_ZA
uct.type.resourceArticleen_ZA
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