Title

Influence of density and major histocompatibility genotype on sexual selection in a salmonid alternative mating strategy

Document Type

Article

Publication Date

2012

Publication Title

Canadian Journal of Fisheries and Aquatic Sciences

Volume

69

Issue

4

First Page

670

Last Page

680

DOI

10.1139/F2012-007

Keywords

body-size; effective population-size; genetic-variation; male atlantic salmon; male fertilization success; mature male parr; reproductive tactics; salar l.; sperm competition; trout oncorhynchus-mykiss

Abstract

Various mechanisms of sexual selection can occur at both the whole organism and gamete levels. Fertilization success in salmonid fishes is largely determined by behavioural competition within and between "fighter" and "sneaker" male strategies, but is also influenced by interactions among gametes. We investigated the influence of density, fighter male presence, and major histocompatibility (MH) genotype on patterns of fertilization success in sneaker Atlantic salmon (Salmo salar). At low density and in the absence of fighter males, monopolization by single sneaker males occurred, suggesting that male-male competition was the main determinant of fertilization success. By contrast, at high density and (or) in the presence of fighter males, several sneakers succeeded in fertilizing eggs. Our study, the first to investigate the role of MH-mediated fertilization for a genetically based alternative male mating strategy, suggests that a larger proportion of eggs were fertilized by sneakers whose MH genotypes were more similar to those of the female than expected by chance. These findings highlight the importance of examining sexual selection under different competitive conditions.

Comments

This is an accepted manuscript version of an aritcle whose version of record was published in:Canadian Journal of Fisheries and Aquatic Sciences: http://dx.doi.org/10.1139/F2012-007