Figure legends
Figure 1. PCA loadings on climatic factors (left) and the
relationship between climatic PC1 and butterfly reflectance mapped on
the butterfly phylogeny (right). The dimensionality of the six
reflectance variables (mean reflectance of dorsal/ventral thorax, basal
wings, and entire wings across 320 – 1050 nm range) was reduced using
PCA. Reflectance PC1 explained 68% of the variation and correlated
strongly with all six reflectance variables (r >
0.71). Colours in the phylogenetic tree indicate climatic PC1, and
colours in the heatmap show butterfly reflectance PC1.
Figure 2. Average reflectance of European butterfly species for
each body region. The colour of each grid (50 × 50 km) represents the
average reflectance (over 320 – 1050 nm) of all butterfly species
assembly found in each grid. The colour code of each map was assigned
using the Jenks natural break classification method to maximise the
variance between each colour class. Red indicates that the butterfly
assemblage in the area has higher reflectance while blue indicates lower
reflectance (N = 343 species).
Figure 3. The relationship between climatic PC1 and the mean
reflectance of each body region of butterflies. The trend lines
represent the prediction from the multivariate phylogenetic regression
models after accounting for the phylogenetic relationships.
Figure 4. The relationship between climatic PC1 and residuals of
the model where near-infrared reflectance (670–1050 nm) was linearly
fitted by log form of visible reflectance (320–680 nm). Only ventral
thorax and ventral basal wing regions showed significant trends. The
trend lines represent the prediction from the PGLS models.
Figure 5. The relationship between climatic PC1 and
ventral-dorsal reflectance differences in butterflies. The difference
was calculated by subtracting dorsal reflectance from ventral
reflectance. The trend lines represent the prediction from the
multivariate phylogenetic regression models.