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Data from: From cryptic to colourful: evolutionary decoupling of larval and adult colour in butterflies

Citation

Medina, Iliana et al. (2020), Data from: From cryptic to colourful: evolutionary decoupling of larval and adult colour in butterflies, Dryad, Dataset, https://doi.org/10.5061/dryad.c866t1g3c

Abstract

Many animals undergo complete metamorphosis, where larval forms change abruptly in adulthood. Colour change during ontogeny is common, but there is little understanding of evolutionary patterns in these changes. Here we use data on larval and adult colour for 246 butterfly species (61% of all species in Australia) to test whether the evolution of colour is coupled between life stages. We show that adults are more variable in colour across species than caterpillars and that male adult colour has lower phylogenetic signal. These results suggest that sexual selection is driving colour diversity in male adult butterflies at a broad scale. Moreover, colour similarities between species at the larval stage do not predict colour similarities at the adult stage, indicating that colour evolution is decoupled between young and adult forms. Most species transition from cryptic coloration as caterpillars to conspicuous colouration as adults, but even species with conspicuous caterpillars change to different conspicuous colours as adults. The use of high-contrast coloration is correlated with body size in caterpillars but not adults. Taken together, our results suggest a change in the relative importance of different selective pressures at different life stages, resulting in the evolutionary decoupling of coloration through ontogeny. 

Methods

We collected standarised RGB values from online photographs for 246 species of Australian butterflies and their caterpillars. The sRGB values presented were converted from raw aRGB values and an equation in an R function, which can be sent on request.

butter2_extractecNov11.csv -- dataset with all colours measured, for use in R code

butter2_extractecNov11.xls -- dataset but with metadata as tab

Also included: phylogenies used, file names to match data with phylogeny, R code and R functions employed.

Usage Notes

Column headings for dataset:

species species name, does not match phylogeny so file with names is needed to match
fam family
code code of individual measure
colour general colour measured
percentage area occupied by colour measured
stage life stage measured
Ili_apo aposematism code, not used in analyses but collected (3 highly conspicuous and probably aposematic)
quality quality of the photo , with 3 being the highest quality, analyses of high quality include only those with 3
size_cat caterpillar size
size_adult adult size
measure_code code of measurement, all info combined
fit1$cluster values of colour cluster ID
sR standard R, raw value measured from photo, converted from aRGB
sG standard G, raw value measured from photo, converted from aRGB
sB standard B, raw value measured from photo, converted from aRGB
R_c R value of cluster the colour was assigned to, all analyses done with this RGB coordinates
G_c G value of cluster the colour was assigned to, all analyses done with this RGB coordinates
B_c B value of cluster the colour was assigned to, all analyses done with this RGB coordinates

Funding

Australian Research Council

University of Melbourne