Data from: Assessing the association between animal color and behavior: A meta-analysis of experimental studies

Color varies in pattern and degree across the tree of life. In animals,
genetic variation in color is hypothesized to have pleiotropic effects on
a variety of behaviors, due to shared dependence on underlying biochemical
pathways. Such pleiotropy can constrain the independent evolution of color
and behavior. Although associations between color and behavior have been
reported, this relationship has not yet been addressed across a broad
taxonomic scale with a formal meta-analysis. We used a phylogenetic
meta-analytic approach to examine the relationship between individual
variation in aggressive behavior and variation in multiple colors.
Seventy-four studies met our inclusion criteria (vertebrates = 70;
invertebrates = 4). After accounting for phylogeny and correcting for
publication bias, there was a positive association between measures of
aggression and degree or area of coloration (mean = 0.248, 95% CI =
(0.044, 0.477)). Because this positive association was not restricted to
melanin-based coloration, we conclude that this pattern does not strongly
support the melanin-pleiotropy hypothesis. Because the association was
also not affected by moderators accounting for individual condition,
social rank, or age, the results do not strongly support hypotheses that
condition dependence accounts for relationships between color and
aggressive behavior. The badge of status hypothesis predicts that
arbitrary traits can evolve to signal aggression or social dominance. We
propose that this is the most parsimonious explanation for the patterns we
observe. Because of lack of evidence for condition dependence in the
association between color and aggression, we further propose that the
genetic covariation between traits contributes to the evolution of the
badges of status.