Data to estimate the effect of inbreeding on breeding coloration in sand lizards

Animal color signals may function as indicators of fighting ability when
males compete for access to females. This allows opponents to settle
aggressive interactions before they escalate into physical combat and
injury. Thus, there may be strong directional selection on these traits,
toward enhanced signal quality. This renders sexually selected traits
particularly susceptible to inbreeding depression, due to relatively low
ratios of additive genetic variance to dominance variance. We measured the
effects of inbreeding on an intrasexually selected color signal (the
badge) in a population of Swedish sand lizards (Lacerta agilis) using the
Rhh software based on 17 to 21 microsatellites. Males of this sexually
dichromatic species use the badge during aggressive interactions to
display, and assess, fighting ability. We found negative effects of
homozygosity on badge size, saturation, and brightness. However, no such
effects were observed on color hue. Pairwise correlations between badge
size, hue, and saturation were all statistically significant. Thus, the
sand lizard “badge” is a multicomponent signal with variation explained by
covariation in badge size, saturation, and color hue. Body mass corrected
for skeletal size (body condition) positively predicted badge size and
saturation, encouraging future research on the extent that sexual signals
may convey information on multigene targets (i.e. “genic capture”).