Variation in feather corticosterone levels in Alpine swift nestlings provides support for the hypo-responsive hypothesis

Acknowledgements: The authors would like to thank the numerous students who helped collecting data in the field and the city council of Solothurn for access the Bieltor tower. SJE would like to thank Benedetta Catitti for producing the figures and Lukas Jenni for valuable comments on the manuscript. This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.Peer reviewedPostprintPublisher PD

Data from: Heterozygosity and survival in blue tits (Cyanistes caeruleus): contrasting effects of presumably functional and neutral loci

The relationship between genetic diversity and fitness has important implications in evolutionary and conservation biology. This relationship has been widely investigated at the individual level in studies of heterozygosity-fitness correlations (HFC). General effects due to inbreeding and/or local effects at single loci have been used as explanations of HFC, but the debate about the causes of HFC in open, natural populations is still ongoing. Study designs that control for variation in the inbreeding level of the individuals, and knowledge on the function and location of the markers used to measure heterozygosity, are fundamental to understand the causes of HFC. Here we investigated correlations between individual heterozygosity and estimates of survival at different life-history stages in an open population of blue tits (Cyanistes caeruleus). For survival at the embryo, nestling and fledgling stage we used a full-sibling approach, i.e. we controlled for the level of inbreeding. We genotyped 1496 individuals with 79 microsatellites distributed across 25 chromosomes in another passerine and classified either as potentially functional (58 loci) or neutral (21 loci). We found different effects of standardized multilocus heterozygosity (SH): SHfunctional had a negative effect on the probability of hatching and local recruitment of females, whereas SHneutral had a positive effect on adult survival. The negative effects of functional loci are better explained by local effects, whereas the positive effects of neutral markers could reflect inbreeding effects in the population. Our results highlight the importance of considering the characteristics of the markers used in HFC studies and confirm the mixed effects of heterozygosity in different contexts (e.g. sex and life-history stage)

Data from: Correlations between heterozygosity and reproductive success in the blue tit (Cyanistes caeruleus): an analysis of inbreeding and single locus effects

In order to understand the mechanisms behind heterozygosity-fitness correlations (HFC), it is necessary to employ large numbers of markers with known function and to independently estimate the variation in inbreeding in the population. Here we genotyped 794 blue tits with 79 microsatellites that were distributed across 25 chromosomes and that were classified either as "functional" (N = 58) or "neutral" (N = 21). We found a positive effect of individual heterozygosity at multiple loci on clutch size, on the number of eggs sired by males, and on the number of recruits produced by males and females. We documented the occurrence of some consanguineous matings and found evidence for a particular type of population structure that can contribute to the occurrence of inbreeding. As the set of "neutral" loci provided more power to detect HFC and identity disequilibrium, we argue that "neutral" markers are better predictors of the effects of inbreeding. The number of significant effects at single loci did not exceed the expected number of false positives and no strong effects were associated with heterozygosity at "functional" markers. Thus, the HFC found here cannot be attributed to strong effects of the loci under study

Yearling survival data

Survival until next breeding seasons (survival) are listed for all yearlings. Year of first breeding season (season), sex (1 = male, 2 = female) and recruitment status (1 = local recruit, 0 = immigrant) are added

Reproductive success of each nest (breeding pair)

Reproductive success information per nest is given as clutch size, no. of hatchlings, no. of fledglings and no. of recruits to the next breeding season. Age is coded as 1 (one year old) or 2 (two or more years old)

Clutch sizes of all females and breeding seasons

Clutch sizes (no. of eggs) per female and breeding season are listed. Age of the female is coded as 1 (one year old) or 2 (two or more years old)

Sired eggs of all males and breeding seasons

Number sired eggs per male and breeding season is listed. Age of the male is coded as 1 (one year old) or 2 (two or more years old)

Early survival data

Survival until hatching (hatched), survival until fledging (fledged) and survival until first breeding season (recruited) are listed for each chick. Year of birth (season), fledging mass at day 14, clutch size and z-transformed laying date are added when used in the analyses

Single-locus heterozygosity of all individuals

Heterozygosity information is given as homozygote (0) or heterozygote (1) for all loci. Loci names see publication, table 1

Single-locus heterozygosity of all individuals

Heterozygosity (0 = homozygous and 1 = heterozygous) for all individuals and loci. Loci names see Olano-Marin et al. 2011, table 1