Data from: Sex-specific additive genetic variances and correlations for fitness in a song sparrow (Melospiza melodia) population subject to natural immigration and inbreeding

Quantifying sex-specific additive genetic variance (VA) in fitness, and
the cross-sex genetic correlation (rA), is prerequisite to predicting
evolutionary dynamics and the magnitude of sexual conflict. Further,
quantifying VA and rA in underlying fitness components, and genetic
consequences of immigration and resulting gene flow, is required to
identify mechanisms that maintain VA in fitness. However, these key
parameters have rarely been estimated in wild populations experiencing
natural environmental variation and immigration. We used comprehensive
pedigree and life history data from song sparrows (Melospiza melodia) to
estimate VA and rA in sex-specific fitness and underlying fitness
components, and to estimate additive genetic effects of immigrants
alongside inbreeding depression. We found evidence of substantial VA in
female and male fitness, with a moderate positive cross-sex rA. There was
also substantial VA in male but not female adult reproductive success, and
moderate VA in juvenile survival but not adult annual survival. Immigrants
introduced alleles with negative additive genetic effects on local
fitness, potentially reducing population mean fitness through migration
load, but alleviating expression of inbreeding depression. Our results
show that VA for fitness can be maintained in the wild, and be broadly
concordant between the sexes despite marked sex-specific VA in
reproductive success.