title: Genetic variation in variability: Phenotypic variability of fledging weight and its evolution in a songbird population.
abstract: Variation in traits is essential for natural selection to operate and genetic and environmental effects can contribute to this phenotypic variation. From domesticated populations, we know that families can differ in their level of within-family variance, which leads to the intriguing situation that within-family variance can be heritable. For offspring traits, such as birth weight, this implies that within-family variance in traits can vary among families and can thus be shaped by natural selection. Empirical evidence for this in wild populations is however lacking. We investigated whether within-family variance in fledging weight is heritable in a wild great tit (Parus major) population and whether these differences are associated with fitness. We found significant evidence for genetic variance in within-family variance. The genetic coefficient of variation (GCV) was 0.18 and 0.25, when considering fledging weight a parental or offspring trait, respectively. We found a significant quadratic relationship between within-family variance and fitness: families with low or high within-family variance had lower fitness than families with intermediate within-family variance. Our results show that within-family variance can respond to selection and provides evidence for stabilizing selection on within-family variance.
authors.affiliation: Animal Breeding and Genomics Centre, Wageningen University and Research, P.O. Box 338, 6700 AH, Wageningen, The Netherlands. Han.mulder@wur.nl.
authors.forename: Han A
authors.initials: HA
authors.lastname: Mulder
authors.affiliation: Animal Breeding and Genomics Centre, Wageningen University and Research, P.O. Box 338, 6700 AH, Wageningen, The Netherlands.|Department of Animal Ecology, Netherlands Institute of Ecology (NIOO-KNAW), P.O. Box 50, 6700 AB, Wageningen, The Netherlands.
authors.forename: Philip
authors.initials: P
authors.lastname: Gienapp
authors.affiliation: Animal Breeding and Genomics Centre, Wageningen University and Research, P.O. Box 338, 6700 AH, Wageningen, The Netherlands.|Department of Animal Ecology, Netherlands Institute of Ecology (NIOO-KNAW), P.O. Box 50, 6700 AB, Wageningen, The Netherlands.
authors.forename: Marcel E
authors.initials: ME
authors.lastname: Visser
mesh_terms: D000818:Animals; D005075:Biological Evolution; D001835:Body Weight; D014644:Genetic Variation; D009426:Netherlands; D019655:Quantitative Trait, Heritable; D012641:Selection, Genetic; D020308:Songbirds / Q000235:genetics / Q000502:physiology*
keywords: Body mass; evolution; fitness; natural population; residual variance; songbird