Borgi Marta, Majolo Bonaventura
School of Psychology, University of Lincoln, Lincoln, United Kingdom; Department of Cell Biology and Neurosciences, Istituto Superiore di Sanità, Rome, Italy.
School of Psychology, University of Lincoln , Lincoln , United Kingdom.
PeerJ. 2016 Mar 21;4:e1775. doi: 10.7717/peerj.1775. eCollection 2016.
Background. Physical, visual, chemical, and auditory cues signalling fighting ability have independently evolved in many animal taxa as a means to resolve conflicts without escalating to physical aggression. Facial width-to-height ratio (fWHR, i.e., the relative width to height of the face) has been associated with dominance-related phenotypes both in humans and in other primates. In humans, faces with a larger fWHR are perceived as more aggressive. Methods. We examined fWHR variation among 11 species of the genus Macaca. Macaques have been grouped into four distinct categories, from despotic to tolerant, based on their female dominance style. Female dominance style is related to intra- and inter-sexual competition in both males and females and is the result of different evolutionary pressure across species. We used female dominance style as a proxy of intra-/inter-sexual competition to test the occurrence of correlated evolution between competitive regimes and dominance-related phenotypes. fWHR was calculated from 145 2D photographs of male and female adult macaques. Results. We found no phylogenetic signal on the differences in fWHR across species in the two sexes. However, fWHR was greater, in females and males, in species characterised by despotic female dominance style than in tolerant species. Discussion. Our results suggest that dominance-related phenotypes are related to differences in competitive regimes and intensity of inter- and intra-sexual selection across species.
背景。在许多动物分类群中，用于表明战斗能力的物理、视觉、化学和听觉信号已独立进化，作为一种在不升级为身体攻击的情况下解决冲突的方式。面部宽高比（fWHR，即面部的相对宽度与高度）在人类和其他灵长类动物中均与优势相关表型有关。在人类中，fWHR较大的面部被认为更具攻击性。方法。我们研究了猕猴属11个物种的fWHR变异情况。猕猴根据其雌性优势风格被分为从专制到宽容的四个不同类别。雌性优势风格与雄性和雌性的性别内和性别间竞争有关，并且是跨物种不同进化压力的结果。我们使用雌性优势风格作为性别内/性别间竞争的代理，以测试竞争机制与优势相关表型之间的协同进化情况。fWHR是根据145张成年雄性和雌性猕猴的二维照片计算得出的。结果。我们在两性的跨物种fWHR差异上未发现系统发育信号。然而，在具有专制雌性优势风格的物种中，雌性和雄性的fWHR均大于宽容物种。讨论。我们的结果表明，优势相关表型与跨物种的竞争机制以及性别间和性别内选择强度的差异有关。
