Assis Braulio A, Avery Julian D, Tylan Catherine, Engler Heather I, Earley Ryan L, Langkilde Tracy
Department of Biology The Pennsylvania State University University Park PA USA.
Intercollege Graduate Degree Program in Ecology The Pennsylvania State University University Park PA USA.
Ecol Evol. 2021 May 2;11(12):7647-7659. doi: 10.1002/ece3.7598. eCollection 2021 Jun.
Sex differences in animal coloration often result from sex-dependent regulatory mechanisms. Still, some species exhibit incomplete sexual dimorphism as females carry a rudimentary version of a costly male trait, leading to intralocus sexual conflict. The underlying physiology and condition dependence of these traits can inform why such conflicts remain unresolved. In eastern fence lizards (), blue iridophore badges are found in males and females, but melanin pigmentation underneath and surrounding badges is male-exclusive. We track color saturation and area of badges across sexual maturity, and their relationship to individual quality (body condition and immunocompetence) and relevant hormones (testosterone and corticosterone). Saturation and testosterone were positively correlated in both sexes, but hormone and trait had little overlap between males and females. Saturation was correlated with body condition and immunocompetence in males but not in females. Co-regulation by androgens may have released females from resource allocation costs of color saturation, even when in high condition. Badge area was independent of testosterone, but associated with low corticosterone in females, indicating that a nonsex hormone underlies incomplete sexual dimorphism. Given the evidence in this species for female reproductive costs associated with ornamentation, this sex-nonspecific regulation of an honest signal may underlie intralocus sexual conflict.
动物体色的性别差异通常源于性别依赖的调控机制。然而，一些物种表现出不完全的性二态性，因为雌性具有一种代价高昂的雄性特征的雏形版本，从而导致基因座内的性冲突。这些特征潜在的生理机能和条件依赖性可以解释为什么这种冲突仍未得到解决。在东部围栏蜥蜴中，雄性和雌性都有蓝色虹彩细胞斑块，但斑块下方和周围的黑色素沉着是雄性独有的。我们追踪了性成熟过程中斑块的颜色饱和度和面积，以及它们与个体质量（身体状况和免疫能力）和相关激素（睾酮和皮质酮）的关系。饱和度和睾酮在两性中均呈正相关，但雄性和雌性之间激素和特征的重叠很少。饱和度与雄性的身体状况和免疫能力相关，但与雌性无关。雄激素的共同调节可能使雌性从颜色饱和度的资源分配成本中解脱出来，即使在身体状况良好时也是如此。斑块面积与睾酮无关，但与雌性的低皮质酮有关，这表明一种非性激素是不完全性二态性的基础。鉴于该物种存在与装饰相关的雌性生殖成本的证据，这种诚实信号的性别非特异性调节可能是基因座内性冲突的基础。
