Mimicry can occur in several contexts, including sexual interactions. In some cases, males mimic females to gain access to potential mates. In contrast, there are relatively few examples of species where females mimic males, and we know very little about what drives these patterns. Two hypotheses have been advanced to explain female mimicry of males. The first is that mimicry is used to reduce harassment of females by males. The second is that mimicry is used to display dominance over other females. In this study, we tested these hypotheses in Brachyrhaphis fishes, wherein females of several species have pigmentation on their anal fin of the same coloration and shape, and in the same location, as the genitalia of males. To test if female mimicry of males reduces male harassment, we experimentally manipulated female pigmentation and observed male preference for females with and without male-like pigmentation. To test the effect that female mimicry of males has on female dominance, we observed how females respond to anal fin pigmentation patterns of companion females. We found that neither of these hypotheses was supported by our data. We conclude that similarities in anal fin pigmentation between male and female Brachyrhaphis fishes is not an adaptation to reduce male harassment or to signal dominance between females. Alternative explanations must exist, including the possibility that these similarities are simply non-adaptive.

模仿可能发生在多种情况下，包括性互动。在某些情况下，雄性会模仿雌性以获得潜在的配偶。相比之下，雌性模仿雄性的物种例子相对较少，而且我们对驱动这些模式的因素知之甚少。人们提出了两种假设来解释女性对男性的模仿。首先，模仿是用来减少男性对女性的骚扰。第二个是模仿被用来显示对其他女性的统治地位。在这项研究中，我们在短吻鱼中测试了这些假设，其中几种雌性的臀鳍上都有与雄性生殖器相同的颜色和形状以及相同位置的色素沉着。为了测试女性对男性的模仿是否会减少男性骚扰，我们通过实验操纵女性色素沉着，并观察男性对有或没有类似男性色素沉着的女性的偏好。为了测试雌性对雄性的模仿对雌性统治地位的影响，我们观察了雌性对雌性同伴肛鳍色素沉着模式的反应。我们发现这些假设都没有得到我们的数据的支持。我们得出的结论是，雄性和雌性短尾鮈鱼臀鳍色素沉着的相似性并不是为了减少雄性骚扰或表明雌性之间的主导地位而进行的适应。必须存在替代解释，包括这些相似之处根本不具有适应性的可能性。