Ramírez-Ponce Andrés, Garfias-Lozano Gabriela, Contreras-Ramos Atilano
Catedrático CONACYT, Laboratorio Regional de Biodiversidad y Cultivo de Tejidos Vegetales, Instituto de Biología, UNAM, Santa Cruz Tlaxcala, Tlaxcala, Mexico.
Recent graduate, Licenciatura en Biología, Facultad de Ciencias, UNAM, Mexico City, Mexico.
PLoS One. 2017 Feb 17;12(2):e0172388. doi: 10.1371/journal.pone.0172388. eCollection 2017.
The origin and function of exaggerated traits exhibited by a great number of species with sexual dimorphism remain largely unexplored. The usual model considered as the evolutionary mechanism for the development of these structures is sexual selection. The nature of growth of the postocular flange (POF) in three species of the dobsonfly genus Platyneuromus (Megaloptera, Corydalidae, Corydalinae) is analyzed to explore sexual size dimorphism and allometric scaling. Results involve positive allometry of POF in males of two species, and negative allometry in males of one species, in general with a female-biased sexual dimorphism. We suggest an ancestral condition of dual incipient ornamentation in Platyneuromus, with a subsequent departure of size and shape of POF in males, triggered by sexual selection. Different sexual selection intensities may explain the parallel or divergent growth of POF within the scheme of dual ornamentation. Empirical behavioral data as well as a phylogenetic framework are necessary to clarify possible causes of phenotypic development, time of origin, and evolution of the POF.
大量具有两性异形的物种所表现出的夸张特征的起源和功能在很大程度上仍未得到探索。通常被认为是这些结构发育的进化机制的模型是性选择。分析了扁翅蛉属（广翅目，齿蛉科，齿蛉亚科）三个物种的眼后凸缘（POF）的生长性质，以探讨两性体型差异和异速生长比例。结果表明，两个物种的雄性POF呈正异速生长，一个物种的雄性呈负异速生长，总体上两性异形偏向雌性。我们认为扁翅蛉存在双重初始装饰的祖先状态，随后雄性POF的大小和形状发生变化，这是由性选择引发的。不同的性选择强度可能解释了在双重装饰模式下POF的平行或发散生长。需要实证行为数据以及系统发育框架来阐明POF表型发育的可能原因、起源时间和进化过程。
