Data and original code for: Explaining the diversity of optical effects in Christmas beetles: climate, history, and mechanisms

Beetles exhibit an extraordinary diversity of brilliant and colourful appearances. The mechanisms producing these optical effects have received some attention, but we know little about the ecological variables driving their evolution. Here we investigated environmental correlates of reflectivity and circular polarization produced by a combination of pigments and structures in optically diverse Christmas beetles (Scarabaeidae: Rutelinae). We quantified the optical properties of 261 specimens representing 46 species using spectrophotometry and calibrated photographs. Then, we examined associations between these properties and environmental variables such as temperature, humidity, and vegetation cover, controlling for body size and phylogenetic relatedness. Our results showed that larger beetles have higher reflectivity and occur in drier environments. Unexpectedly, near-infrared (NIR) reflectivity was not correlated with ecological variables. We observed no universal ecogeographical patte..., This data set was collected from 261 specimens of Australian scarabs representing 53 morphs of 46 species and 9 genera of the subfamily Rutelinae and one species of the subfamily Melolonthinae. 
Reflectivity and transmissivity were collected with spectroscopy methods. Absorptivity was calculated based on these two variables
Circular polarization was studied using calibrated photographs of the beetle specimens in three filters, visible light, left-handed polarized visible light, and right-handed polarized visible light.
The length of the beetles was calculated from the calibrated photographs and used as an indication of size. 
Climate data was extracted from ALA and BioClim. The original code is attached. 
Phylogenetic data was reconstructed from published COI data and additional sequences available in NCBI
Processing:
The linearization and equalization of the photographs were done with a custom-made protocol in MatLab.
Most of the processing of the data was done in R Statistical Softwa..., , # Data and original code for: Explaining the diversity of optical effects in Christmas beetles: climate, history, and mechanisms

[https://doi.org/10.5061/dryad.rv15dv4f7](https://doi.org/10.5061/dryad.rv15dv4f7)

This data set contains all the original files used in our manuscript. Despite the increasing number of studies on natural photonic structures, we seldom know the biological relevance or ecological drivers of these structures. In this study, we used a macroecological approach to look for potential ecological drivers of unique optical effects in 261 specimens representing 46 species of Australian scarabs, known as Christmas beetles (Scarabaeidae: Rutelinae).

This set contains the raw values of reflectance and transmittance measured with spectrometry techniques. As well as the correspondent reflectivity, transmissivity, and absorptivity (integrated across the wavelength range of the solar irradiance). In addition, it contains the raw RGB values extracted from calibrated photogra...