title: Cryptic female choice enhances fertilization success and embryo survival in chinook salmon.
abstract: In this study, we investigated two potentially important intersexual postcopulatory gametic interactions in a population of chinook salmon (Oncorhynchus tshawytscha): (i) the effect of female ovarian fluid (OF) on the behaviour of spermatozoa during fertilization and (ii) the effects of multilocus heterozygosity (MLH) (as an index of male quality) and female-male genetic relatedness on sperm behaviour and male fertilization success when there is sperm competition in the presence of that OF. To do this, we conducted a series of in vitro competitive fertilization experiments and found that, when ejaculates from two males are competing for access to a single female's unfertilized eggs, fertilization success was significantly biased towards the male whose sperm swam fastest in the female's OF. Embryo survival--a measure of fitness--was also positively correlated with both sperm swimming speed in OF and male MLH, providing novel evidence that cryptic female choice is adaptive for the female, enhancing the early survival of her offspring and potentially influencing her fitness.
authors.affiliation: Department of Anatomy, University of Otago, Dunedin, New Zealand Allan Wilson Centre for Molecular Ecology and Evolution, Department of Anatomy University of Otago, Dunedin, New Zealand patrice.rosengrave@otago.ac.nz.
authors.forename: Patrice
authors.identifier: http://orcid.org/0000-0001-8421-3094
authors.initials: P
authors.lastname: Rosengrave
authors.affiliation: Department of Biology, Queen's University, Kingston, Ontario, Canada K7 L 3N6.
authors.forename: Robert
authors.identifier: http://orcid.org/0000-0003-4701-4525
authors.initials: R
authors.lastname: Montgomerie
authors.affiliation: Department of Anatomy, University of Otago, Dunedin, New Zealand Allan Wilson Centre for Molecular Ecology and Evolution, Department of Anatomy University of Otago, Dunedin, New Zealand.
authors.forename: Neil
authors.identifier: http://orcid.org/0000-0003-0671-3637
authors.initials: N
authors.lastname: Gemmell
mesh_terms: D000818:Animals; D004625:Embryo, Nonmammalian / Q000502:physiology; D005260:Female; D005306:Fertilization; D006579:Heterozygote; D008136:Longevity; D008297:Male; D052586:Mating Preference, Animal; D012474:Salmon / Q000235:genetics / Q000254:growth & development / Q000502:physiology*; D013081:Sperm Motility; D013094:Spermatozoa / Q000502:physiology
keywords: cryptic female choice; embryo survival; ovarian fluid; salmon; sexual selection; sperm competition