Qualitative population divergence in proximate determination of a sexually selected trait in the collared flycatcher

Abstract

We examined proximate determination of sexually selected forehead patch size in a Central-European population of Ficedula albicollis, the collared flycatcher, using a 9-year database, and compared our results with those obtained in other populations of the same and the sister species. Betweenindividual variation of forehead patch size was large, its repeatability larger than, and heritability similar to the Swedish population. Unlike in the other populations, the trait proved unaffected by body condition, and only very slightly influenced by age. There was no relationship between forehead patch size and breeding lifespan, and a marginal negative association with survivorship in adult males. Our results suggest that additive genetic variance of the trait in this population is large, but genes act independently of body condition, and there is no viability indicator value of the trait. This is the first report of a qualitative intraspecific difference in proximate determination of a sexually selected trait.

Lifetime offspring production in relation to breeding lifespan, attractiveness, and mating status in male collared flycatchers

“…Whereas studies in a population in Gotland, Sweden, showed that the size of this trait was a good indicator of phenotypic quality (Gustafsson et al 1995;Qvarnström 1999; also see Gustafsson and Qvarnström 2006), this is not the case in our population (Hegyi et al 2002(Hegyi et al , 2006a, although the trait is an important determinant of social mating success (Hegyi et al 2010). The male forehead patch size was estimated as the product of its maximum height and maximum width.…”

“…This species is ideal for long-term studies of reproductive success. It shows a preference for nestboxes, can easily be captured, and has high breeding-site fidelity (Pärt and Gustafsson 1989;Könczey et al 1992;Hegyi et al 2002) and considerable local recruitment rates (Pärt 1990;Török et al 2004). Nestboxes were checked multiple times a week throughout the nesting period, so breeding attempts were followed from nest building to fledging.…”

“…Because of the high site fidelity of breeding males (Könczey et al 1992;Hegyi et al 2002) and the high capture effort in our population, birds that bred in one of our study plots in a given year but were not recaptured in subsequent years were considered dead. We tested if including cohorts (year of birth) in the analyses changed the results.…”

“…We measured the LRS as the number of lifetime recruits, and examined how individual variation in LRS was explained by differences in breeding lifespan. We were also interested in how the lifetime success was impacted by body size, forehead patch size (a sexually selected character; Hegyi et al 2002), and polygyny, which is a regularly encountered reproductive status of males (Garamszegi et al 2004). …”

Heritability and genetic correlation between the sexes in a songbird sexual ornament

“…Potti, 1993;Morales et al, 2007). Once that genetic and environmental contributions to ornament size in blackand-white European Ficedula species are beginning to be understood (Sheldon et al, 1997;Qvarnströ m, 1999;Hegyi et al, 2002;Saetre et al, 2003;Saether et al, 2007; this study), the biggest challenge is now for researchers to explain the within and between-population differences in the degree of inhibition (Williams and Carroll, 2009) of ornament displaying in females, a trait that we show is apparently subject to large environmental/nonadditive genetic variance(s). When optimal trait expression differs between the sexes, between-sex population variation in its degree might cause geographically variable antagonistic selection , wherein genetic factors spread across populations by giving a reproductive advantage to males while disadvantaging females or vice versa.…”