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104 results for “blue tit”

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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.

opencc-zeroDec 2010View details →

dryad28/100

Data from: MHC-I provides both quantitative resistance and susceptibility to blood parasites in blue tits in the wild

Major histocompatibility complex (MHC) genes are central for the adaptive immune response against parasites. Here, we investigated potential associations among MHC-I alleles and blood parasite infections in a natural breeding population of a passerine bird, the blue tit Cyanistes caeruleus, in central Spain. We screened both infection status (presence/absence of infection) and infection intensity to the pathogenic blood parasites Haemoproteus and Leucocytozoon. Three MHC-I alleles (UA104, UA108 and UA117) were associated with higher or lower infection intensities by Leucocytozoon. Interestingly, these associations were dependent on age and were found both among young and adult birds. No MHC alleles were associated with infection intensity by Haemoproteus parasites. In addition, no significant relationships were detected between infection status by Haemoproteus and Leucocytozoon infections and MHC alleles. The very high prevalence of these two parasites in our study population (79–100%) poses challenges to identify associations with infection status and also suggests that clearance of infections may be rare. In conclusion, associations between specific MHC-I alleles and Leucocytozoon parasites were related to either high or low infection intensities, and hence increased susceptibility or resistance to infection.

opencc-zeroDec 2015View details →

dryad28/100

Data from: No evidence for sibling or parent-offspring coadaptation in a wild population of blue tits, despite high power.

Parent and offspring behaviours are expected to act as both the agents and targets of selection. This may generate parent-offspring coadaptation in which parent and offspring behaviours become genetically correlated in a way that increases inclusive fitness. Cross-fostering has been used to study parent-offspring coadaptation, with the prediction that offspring raised by non-relatives, or parents raising non-relatives, should suffer fitness costs. Using long-term data from more than 400 partially crossed broods of blue tits (Cyanistes caeruleus) we show there is no difference in mass or survival between crossed and non-crossed chicks. However, previous studies for which the evidence for parent-offspring coadaptation is strongest compare chicks from fully crossed broods with those from non-crossed broods. When parent-offspring coadaptation acts at the level of the brood then partial cross-fostering experiments are not expected to show evidence of coadaptation. To test this, we performed an additional cross-fostering experiment (163 broods) in which clutches were either fully crossed, non-crossed, or partiallycrossed. In agreement with the long-term data, there was no evidence for parent-offspring coadaptationon offspring fitness depsite high power. In addition there was no evidence of effects on parental fitness, nor evidnce of sibling coadaptation, although the power of these tests was more modest.

opencc-zeroDec 2017View details →

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Data from: Characterization of the genome and transcriptome of the blue tit Cyanistes caeruleus: polymorphisms, sex-biased expression and selection signals

Decoding genomic sequences and determining their variation within populations has potential to reveal adaptive processes and unravel the genetic basis of ecologically relevant trait variation within a species. The blue tit Cyanistes caeruleus – a long-time ecological model species – has been used to investigate fitness consequences of variation in mating and reproductive behaviour. However, very little is known about the underlying genetic changes due to natural and sexual selection in the genome of this songbird. As a step to bridge this gap, we assembled the first draft genome of a single blue tit, mapped the transcriptome of five females and five males to this reference, identified genomewide variants and performed sex-differential expression analysis in the gonads, brain and other tissues. In the gonads, we found a high number of sex-biased genes, and of those, a similar proportion were sex-limited (genes only expressed in one sex) in males and females. However, in the brain, the proportion of female-limited genes within the female-biased gene category (82%) was substantially higher than the proportion of male-limited genes within the male-biased category (6%). This suggests a predominant on-off switching mechanism for the female-limited genes. In addition, most male-biased genes were located on the Z-chromosome, indicating incomplete dosage compensation for the male-biased genes. We called more than 500 000 SNPs from the RNA-seq data. Heterozygote detection in the single reference individual was highly congruent between DNA-seq and RNA-seq calling. Using information from these polymorphisms, we identified potential selection signals in the genome. We list candidate genes which can be used for further sequencing and detailed selection studies, including genes potentially related to meiotic drive evolution. A public genome browser of the blue tit with the described information is available at http://public-genomes-ngs.molgen.mpg.de.

opencc-zeroDec 2014View details →

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Data from: Accuracy of background matching and prey detection: predation by blue tits (Cyanistes caeruleus) indicates intense selection for highly matching prey colour pattern

1. Although background matching decreases prey detectability, resemblance between camouflaged prey and their visual background is seldom perfect. This could be because even a moderate resemblance might provide sufficient protection, and additional adjustment of colour pattern might give little benefit. Alternatively, close resemblance to background may not be attained due to trade-offs or constraints. To understand selection on colour patterns of camouflaged prey and the existence of inaccurate background matching, it is necessary to investigate how detectability of a colour pattern varies with its resemblance to the background. 2. We trained wild-caught blue tits (Cyanistes caeruleus) to search for artificial prey. We manipulated the resemblance of the artificial prey items to the visual backgrounds. 3. For the first half of the twelve repeated prey presentations we found a non-linear relationship between resemblance and detectability, such that for prey that had high background matching, a change in resemblance resulted in a larger change in detectability than an equal change in resemblance did for prey with lower background matching. However, for the second half of the presentations this relationship was linear. Moreover, in a two-patch-type habitat a prey pattern that was a compromise between the two different backgrounds did after few initial presentations equally well as the prey pattern that matched highly one of the backgrounds. 4. Our results indicate an intense selection for close matching in a single background. Yet, in the heterogeneous environment that consisted of two backgrounds the compromise, which only loosely resembled either background, provided good protection. Therefore, we conclude that cryptic colour patterns that bear only a loose resemblance to a given background, and thus represent inaccurate background matching, may be adaptive outcomes.

opencc-zeroDec 2013View details →

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