Egg production and individual genetic diversity in lesser kestrels

Abstract

Fecundity is an important component of individual fitness and has major consequences on population dynamics. Despite this, the influence of individual genetic variability on egg production traits is poorly known. Here, we use two microsatellite-based measures, homozygosity by loci and internal relatedness, to analyse the influence of female genotypic variation at 11 highly variable microsatellite loci on both clutch size and egg volume in a wild population of lesser kestrels (Falco naumanni). Genetic diversity was associated with clutch size, with more heterozygous females laying larger clutches, and this effect was statistically independent of other nongenetic variables such as female age and laying date, which were also associated with fecundity in this species. However, egg volume was not affected by female heterozygosity, confirming previous studies from pedigree-based breeding experiments which suggest that this trait is scarcely subjected to inbreeding depression. Finally, we explored whether the association between heterozygosity and clutch size was due to a genome-wide effect (general effect) or to single locus heterozygosity (local effect). Two loci showed a stronger influence but the correlation was not fully explained by these two loci alone, suggesting that a main general effect underlies the association observed. Overall, our results underscore the importance of individual genetic variation for egg production in wild bird populations, a fact that could have important implications for conservation research and provides insights into the study of clutch size evolution and genetic variability maintenance in natural populations.

What keeps ‘living dead’ alive: demography of a small and isolated population of Maculinea (= Phengaris) alcon

“…ongoing climate change (Cobben et al 2012). Furthermore, low genetic variability may also lead to decreased individual fitness (Lacy 1997;Ortego et al 2007). A potential manifestation of the above principle could be the very low female fecundity that we recorded in the present study, although we do not have any direct evidence for its genetic basis.…”

A quantitative review of heterozygosity–fitness correlations in animal populations

“…It is thus surprising that many studies have pooled samples from multiple populations or subpopulations (e.g. Acevedo-Whitehouse et al 2005; Gage et al 2006;Ortego et al 2007;Välimäki et al 2007). Demographic impacts on the strength of HFCs may be obscured in such studies.…”

Viability selection creates negative heterozygosity–fitness correlations in female Black Grouse Lyrurus tetrix

“…We also found a negative relationship between heterozygosity and egg volume, with weak negative trends for egg mass. While several studies have reported a positive relationship between clutch size and heterozygosity (Foerster et al 2003;Ortego et al 2007;Wetzel et al 2012), few studies have examined the relationship between heterozygosity and other clutch parameters. Indeed, the only other clutch parameter examined was egg size, and some studies found a positive effect of heterozygosity (Forstmeier et al 2012;Wetzel et al 2012) or no effect (Ortego et al 2007) probably because individuals trade-off egg size with clutch size (Smith et al 1989;Nager et al 2000).…”

“…Mojica and Kelly 2010). In studies investigating HFCs, fitness components are often considered separately with, for example, heterozygosity and shortterm survival (Bean et al 2004;Canal et al 2014) or heterozygosity and clutch size (Ortego et al 2007;Wetzel et al 2012). When more complex approaches are undertaken, the traits considered (heterozygosity and morphological traits such as body mass) typically act simultaneously on a single component of fitness such as survival (Richardson et al 2004).…”