DOI: 10.5061/dryad.w6m905qr9
title: Long-term decrease in colouration: A consequence of climate change?

description: Climate change has been shown to affect fitness-related traits in a wide
 range of taxa; for instance, warming leads to phenological advancements in
 many plant and animal species. The influence of climate change on social
 and secondary sexual traits, that are associated with fitness due to their
 role as quality signals, is however unknown. Here, we use more than 5800
 observations collected on two Mediterranean blue tit subspecies (Cyanistes
 caeruleus caeruleus and C. c. ogliastrae) to explore whether blue crown
 and yellow breast patch colourations have changed over the past 15 years.
 Our data suggests that colouration has become duller and less chromatic in
 both sexes. In addition, in the Corsican C.c.ogliastrae, but not in the
 mainland C.c.caeruleus, the decrease is associated with an increase in
 temperature at moult. Quantitative genetic analyses do not reveal any
 microevolutionary change in the colour traits along the study period,
 strongly suggesting that the observed change over time was caused by a
 plastic response to the environmental conditions. Overall, this study
 suggests that ornamental colourations could become less conspicuous due to
 warming, revealing climate change effects on sexual and social ornaments
 and calling for further research on the proximate mechanisms behind these
 effects.
description: This dataset includes 15-years of information about the blue tit
 colouration 
description: # Long-term decrease in colouration: A consequence of climate change?
 [https://doi.org/10.5061/dryad.w6m905qr9](https://doi.org/10.5061/dryad.w6m905qr9) ## Description of the data and file structure Files: 1. code_manuscript: contains the R code used to run the analysis and plots present in the paper, the code also includes a sample code on how to obtain the colour variables from the spectra using pavo. The description of the colour variables can be found in SM-1. 2. data_base_colour.csv: data set containing the information required for running the analyses in sections one, three and four. It contains the following information: a. cod -&gt; identity of the individuals. b. yr/yrcont -&gt; year, one is meant to be coded as a factor and the other one as continuous in the analyses (see code). c. isla -&gt; described whether the observations were obtained from Corsica (isla=2) or Rouviere (isla=1). d. bb -&gt; blue crown brightness (colour variable). e. buvc -&gt; blue crown UC chroma (colour variable). f. yc -&gt; yellow chroma (colour variable). g. yb -&gt; yellow brightness (colour variable). h. agecod -&gt; age of the individuals, coded as one-year old (agecod=1) and more than one-year old (agecod=2). i. meantm1-&gt; average daily temperature in the previous summer (climatic variable). j. meanrr1 -&gt; average daily precipitation in the previous summer (climatic variable). k. site -&gt; study sites in each population (Corsica=d-muro, e-muro, e-pirio; Rouviere=drouviere). l. sex -&gt; the sex of the individuals coded as males=1, females=2. Note: NAs denote values with no information recorded. 3. data_base_climate.csv: data set containing the information required to run the analyses and plots in section two. It contains the following information: a. year-&gt; year. b. meantm-&gt; average summer daily temperature in the current year. c. sdtm-&gt; standard deviation of the summer temperature in the current year. d. meanrr-&gt; average summer daily precipitations in the current year. e. sdrr -&gt; standard deviation of the summer precipitations in the current year. f. n -&gt; sample size. g. setm -&gt; standard error of the summer temperature in the current year. h. serr -&gt; standard error of the summer precipitations in the current year. i. pop -&gt; study population (cors= Corsica; rou=Rouviere). Note: NAs denote values with no information recorded. 4. pedigree_pop.csv: pedigree of the two populations. It contained the following information: a. id-&gt; identity of the individuals. b. dam-&gt; identity of the dams. c. sire-&gt; identity of the sires. Note: NAs denote cell where the mother (dams) and father (sires) information is not known. Information about versions of packages and software used: All analyses were conducted in R statistical software (version 3.6.3), in a platform x86_64-appledarwin15.6.0 (64-bit) running under macOS 10.16. Specifically, we used the following packages: -readr (v. 1.4.0) -lmerTest (v. 3.1-3) -ggplot2 (v. 3.3.2) -dplyr (v. 1.0.2) -usdm (v. 1.1-18) -MuMIn (v. 1.43.17) -MCMCglmm (v. 2.32) -pedantics (v. 1.7)* * ”pedantics” is currently not available in CRAN (11.01.2022), but it can be easily downloaded and installed from //cran.r-project.org/src/contrib/Archive/pedantics/