title: No selection on immunological markers in response to a highly virulent pathogen in an Arctic breeding bird.
abstract: In natural populations, epidemics provide opportunities to look for intense natural selection on genes coding for life history and immune or other physiological traits. If the populations being considered are of management or conservation concern, then identifying the traits under selection (or 'markers') might provide insights into possible intervention strategies during epidemics. We assessed potential for selection on multiple immune and life history traits of Arctic breeding common eiders (Somateria mollissima) during annual avian cholera outbreaks (summers of 2006, 2007 & 2008). We measured prelaying body condition, immune traits, and subsequent reproductive investment (i.e., clutch size) and survival of female common eiders and whether they were infected with Pasteurella multocida, the causative agent of avian cholera. We found no clear and consistent evidence of directional selection on immune traits; however, infected birds had higher levels of haptoglobin than uninfected birds. Also, females that laid larger clutches had slightly lower immune responses during the prelaying period reflecting possible downregulation of the immune system to support higher costs of reproduction. This supports a recent study indicating that birds investing in larger clutches were more likely to die from avian cholera and points to a possible management option to maximize female survival during outbreaks.
authors.affiliation: Département de biologie & Centre d'études nordiques, Université du Québec à Rimouski Rimouski, QC, Canada.
authors.forename: Pierre
authors.initials: P
authors.lastname: Legagneux
authors.affiliation: Environmental and Life Sciences Graduate Program, Trent University Peterborough, ON, Canada.
authors.forename: Lisha L
authors.initials: LL
authors.lastname: Berzins
authors.affiliation: Department of Biology, Carleton University Ottawa, ON, Canada.
authors.forename: Mark
authors.initials: M
authors.lastname: Forbes
authors.affiliation: Department of Veterinary Pathology, University of Saskatchewan Saskatoon, SK, Canada.
authors.forename: Naomi Jane
authors.initials: NJ
authors.lastname: Harms
authors.affiliation: Department of Biological Sciences, University of Windsor Windsor, ON, Canada.
authors.forename: Holly L
authors.initials: HL
authors.lastname: Hennin
authors.affiliation: Norwegian Polar Institute, Fram Centre Tromsø, Norway.
authors.forename: Sophie
authors.initials: S
authors.lastname: Bourgeon
authors.affiliation: National Wildlife Research Centre, Environment Canada Ottawa, ON, Canada.
authors.forename: H G
authors.initials: HG
authors.lastname: Gilchrist
authors.affiliation: Département de biologie & Centre d'études nordiques, Université du Québec à Rimouski Rimouski, QC, Canada.
authors.forename: Joël
authors.initials: J
authors.lastname: Bêty
authors.affiliation: Department of Veterinary Pathology, University of Saskatchewan Saskatoon, SK, Canada ; Environment Canada Saskatoon, SK, Canada.
authors.forename: Catherine
authors.initials: C
authors.lastname: Soos
authors.affiliation: Department of Biological Sciences, University of Windsor Windsor, ON, Canada.
authors.forename: Oliver P
authors.initials: OP
authors.lastname: Love
authors.affiliation: Center for Microbial Genetics & Genomics, Northern Arizona University Flagstaff, AZ, USA.
authors.forename: Jeffrey T
authors.initials: JT
authors.lastname: Foster
authors.affiliation: Norwegian Polar Institute, Fram Centre Tromsø, Norway.
authors.forename: Sébastien
authors.initials: S
authors.lastname: Descamps
authors.affiliation: Department of Biology, Trent University Peterborough, ON, Canada.
authors.forename: Gary
authors.initials: G
authors.lastname: Burness
keywords: Pasteurella multocida; avian cholera; clutch size; common eider (Somateria mollissima); immune traits; natural selection