DOI: 10.5061/dryad.h00nk10
title: Data from: Plumage coloration follows Gloger’s rule in a ring species

description: Aim: Animal coloration is expected to differ between populations in
 different habitats according to Gloger’s rule, with darker animals found
 in more humid, vegetated or warmer environments. Yet despite considerable
 support across the globe, the mechanisms behind this biogeographical rule
 are currently still unclear. Exploiting a ring species with plumage
 coloration from crimson to pale yellow, we test Gloger’s rule and the
 mechanisms behind phenotypic divergence. Location: South-eastern
 Australia. Major taxa studied: Crimson rosellas (Platycercus elegans).
 Methods: We combined three modelling approaches (spatial regression;
 random decision forest species distribution and conditional inference
 tree) to test the association between 10 environmental variables (based on
 long-term climate data and remotely sensed reflectance of the land) and
 plumage coloration across the distribution of P. elegans. We also took
 in-situ measurements of background coloration of dominant vegetation to
 examine the relationship between 1) background coloration measured locally
 and remotely, 2) P. elegans coloration, and 3) known differences in visual
 sensitivity of the subspecies using species-specific visual models.
 Results: On both a continental and a local scale, the distribution of
 yellow-red plumage coloration was strongly predicted by average rainfall,
 summer temperature and the Earth’s reflectance between 620-670nm. Remotely
 sensed radiance measures correlated strongly and positively with
 reflectance of the leaves of the dominant tree species at sites across the
 P. elegans distribution. Visual modelling indicated that differences in
 background colour could affect signalling efficacy in dim-light
 conditions. Main conclusions: Our study shows that the highly variable
 plumage coloration conforms to Gloger’s rule, and indicates that
 background coloration of the vegetation and thermoregulation are likely to
 be important mechanisms. Our results also show that Gloger’s rule can
 explain variation in pigmentary systems other than melanin, and highlight
 that selection from environmental variation could be an important force
 behind the geographic diversity found in ring species.
description: Environmental variables
 and Platycercus elegans plumage colorationDataset containing 10
 environmental variables from 358 grid cells used for analyses of plumage
 color variation in Platycercus elegans across its distribution in
 southeastern Australia. Four P. elegans plumage coloration groups were
 used: 1) YR, 2) AR, 3) WS and 4) CR.Platycercus elegans
 coloration.csvP elegans sites with 3
 environmental variablesDataset with 3
 environmental variables from 33 sites across the distribution of
 Platycercus elegans.P elegans reflectance
 spectra leavesDataset containing
 reflectance spectra of leaves (between 300 and 690nm and divided into 120
 bins of 10nm) measured from dominant trees in the habitat of the four P.
 elegans plumage coloration groups (YR, AR, WS, CR) at three different
 sites per group.P elegans reflectance
 spectra sites and leavesDataset containing
 measurements of MODIS band 1 taken over three different scales (500m,
 5000m and 10000m) and measurements of overall reflectance and reflectance
 between 620-670nm of leaves from dominant trees in the habitat of P.
 elegans.