title: Social pairing of Seychelles warblers under reduced constraints: MHC, neutral heterozygosity, and age.
abstract: The prevalence and significance of precopulatory mate choice remains keenly debated. The major histocompatibility complex (MHC) plays a key role in vertebrate adaptive immunity, and variation at the MHC influences individual survival. Although MHC-dependent mate choice has been documented in certain species, many other studies find no such pattern. This may be, at least in part, because in natural systems constraints may reduce the choices available to individuals and prevent full expression of underlying preferences. We used translocations to previously unoccupied islands to experimentally reduce constraints on female social mate choice in the Seychelles warbler (Acrocephalus sechellensis), a species in which patterns of MHC-dependent extrapair paternity (EPP), but not social mate choice, have been observed. We find no evidence of MHC-dependent social mate choice in the new populations. Instead, we find that older males and males with more microsatellite heterozygosity are more likely to have successfully paired. Our data cannot resolve whether these patterns in pairing were due to male-male competition or female choice. However, our research does suggest that female Seychelles warblers do not choose social mates using MHC class I to increase fitness. It may also indicate that the MHC-dependent EPP observed in the source population is probably due to mechanisms other than female precopulatory mate choice based on MHC cues.
authors.affiliation: School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich, Norfolk NR4 7TJ, UK,; Department of Animal and Plant Sciences, NERC Biomolecular Analysis Facility, University of Sheffield, Sheffield S10 2TN, UK.
authors.forename: David J
authors.initials: DJ
authors.lastname: Wright
authors.affiliation: Evolution, Ecology & Genetics, Research School of Biology, The Australian National University , Canberra, Australian Capital Territory 0200 , Australia .
authors.forename: Lyanne
authors.initials: L
authors.lastname: Brouwer
authors.affiliation: Department of Animal and Plant Sciences, NERC Biomolecular Analysis Facility, University of Sheffield , Sheffield S10 2TN , UK .
authors.forename: Maria-Elena
authors.initials: ME
authors.lastname: Mannarelli
authors.affiliation: Department of Animal and Plant Sciences, NERC Biomolecular Analysis Facility, University of Sheffield , Sheffield S10 2TN , UK .
authors.forename: Terry
authors.initials: T
authors.lastname: Burke
authors.affiliation: Behavioural Ecology and Self-organization Group, Centre for Ecological and Evolutionary Studies, University of Groningen , PO Box 11103, 9700 CC Groningen , The Netherlands , and.
authors.forename: Jan
authors.initials: J
authors.lastname: Komdeur
authors.affiliation: School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich, Norfolk NR4 7TJ, UK,; Nature Seychelles, Centre for Environment and Education, The Sanctuary, PO Box 1310, Roche Caiman, Victoria, Mahé, Republic of Seychelles.
authors.forename: David S
authors.initials: DS
authors.lastname: Richardson
keywords: MHC class I; compatibility; extrapair paternity; good genes; sexual selection; translocation.