Eco-correlates of coloration in primates

Primates are noted for their varied and complex pelage and bare skin
coloration but the significance of this diverse coloration remains opaque.
Using new updated information, novel scoring of coat and skin coloration,
and controlling for shared ancestry, we reexamined and extended findings
from previous studies across the whole order and the five major clades
within it. Across primates we found (i) direct and indirect evidence for
pelage coloration being driven by protective coloration strategies
including background matching, countershading, disruptive coloration and
aposematism, (ii) diurnal primates being more colorful, and (iii) the
possibility that pelage color diversity is negatively associated with
female trichromatic vision; while (iv) reaffirming avoidance of
hybridization driving head coloration in males, (v) darker species living
in warm, humid conditions (Gloger’s rule), and (vi) advertising to
multiple mating partners favoring red genitalia in females. Nonetheless,
the importance of these drivers varies greatly across clades. In
strepsirrhines and cercopithecoids, countershading is important; greater
color diversity may be important for conspecific signaling in more diurnal
and social strepsirrhines; lack of female color vision may be associated
with colorful strepsirrhines and platyrrhines; whereas cercopithecoids
obey Gloger’s rule. Haplorrhines show background matching, aposematism,
character displacement, and red female genitalia where several mating
partners are available. Our findings emphasize several evolutionary
drivers of coloration in this extraordinarily colorful order. Throughout,
we used coarse but rigorous measures of coloration, and our ability to
replicate findings from earlier studies opens up opportunities for
classifying coloration of large numbers of species at a macroevolutionary
scale.