title: Seasonal variation in male alternative reproductive tactics.
abstract: Genetic parentage analyses reveal considerable diversity in alternative reproductive behaviours (e.g. sneaking) in many taxa. However, little is known about whether these behaviours vary seasonally and between populations. Here, we investigate seasonal variation in male reproductive behaviours in a population of two-spotted gobies (Gobiusculus flavescens) in Norway. Male two-spotted gobies guard nests, attract females and care for fertilized eggs. We collected clutches and nest-guarding males early and late in the breeding season in artificial nests and used microsatellite markers to reconstruct parentage from a subset of offspring from each nest. We hypothesized that mating, reproductive success and sneaking should be more prevalent early in the breeding season when competition for mates among males is predicted to be higher. However, parentage analyses revealed similar values of mating, reproductive success and high frequencies of successful sneaking early (30% of nests) and late (27% of nests) in the season. We also found that multiple females with eggs in the same nest were fertilized by one or more sneaker males, indicating that some males in this population engage in a satellite strategy. We contrast our results to previous work that demonstrates low levels of cuckoldry in a population in Sweden. Our results demonstrate marked stability in both the genetic mating system and male alternative reproductive tactics over the breeding season. However, sneaking rates may vary geographically within a species, likely due to local selection influencing ecological factors encountered at different locations.
authors.affiliation: Department of Ecology and Environmental Science, Umeå University, Umeå, Sweden.|Department of Ecology and Genetics, Evolutionary Biology Center, Uppsala University, Uppsala, Sweden.
authors.forename: M J
authors.initials: MJ
authors.lastname: Monroe
authors.affiliation: Department of Biology, Norwegian University of Science and Technology, Trondheim, Norway.
authors.forename: T
authors.initials: T
authors.lastname: Amundsen
authors.affiliation: Department of Biology, University of Bergen, Bergen, Norway.|Institute of Marine Research, Bergen, Norway.
authors.forename: A C
authors.initials: AC
authors.lastname: Utne-Palm
authors.affiliation: Department of Ecology and Environmental Science, Umeå University, Umeå, Sweden.|Department of Evolutionary Ecology, Max Planck Institute for Evolutionary Biology, Plön, Germany.
authors.forename: K B
authors.initials: KB
authors.lastname: Mobley
mesh_terms: D000818:Animals; D005260:Female; D005399:Fishes; D008297:Male; D009664:Norway; D012098:Reproduction; D012621:Seasons; D012641:Selection, Genetic; D012726:Sexual Behavior, Animal; D013548:Sweden
keywords: 
  Gobiusculus flavescens
  ; mating system; microsatellite DNA; parentage; satellite males; sexual selection; sneaking; two-spotted goby