Tsuboi Masahito, Gonzalez-Voyer Alejandro, Kolm Niclas
Evolutionary Biology Centre, Department of Ecology and Genetics/Animal Ecology, Uppsala University, Norbyvägen 18D, 75236 Uppsala, Sweden
Laboratorio de Conducta Animal, Instituto de Ecología, Universidad Nacional Autónoma de México, Circuito Exterior S/N, Ciudad Universitaria, UNAM, D.F. 04510, México Department of Zoology/Ethology, Stockholm University, Svante Arrhenius väg 18B, 10691 Stockholm, Sweden.
Biol Lett. 2015 May;11(5):20141053. doi: 10.1098/rsbl.2014.1053.
Functional coupling, where a single morphological trait performs multiple functions, is a universal feature of organismal design. Theory suggests that functional coupling may constrain the rate of phenotypic evolution, yet empirical tests of this hypothesis are rare. In fish, the evolutionary transition from guarding the eggs on a sandy/rocky substrate (i.e. substrate guarding) to mouthbrooding introduces a novel function to the craniofacial system and offers an ideal opportunity to test the functional coupling hypothesis. Using a combination of geometric morphometrics and a recently developed phylogenetic comparative method, we found that head morphology evolution was 43% faster in substrate guarding species than in mouthbrooding species. Furthermore, for species in which females were solely responsible for mouthbrooding the males had a higher rate of head morphology evolution than in those with bi-parental mouthbrooding. Our results support the hypothesis that adaptations resulting in functional coupling constrain phenotypic evolution.
功能耦合是生物体设计的一个普遍特征，即单一形态特征执行多种功能。理论表明，功能耦合可能会限制表型进化的速率，但对这一假设的实证检验却很少见。在鱼类中，从在沙地/岩石基质上守护鱼卵（即基质守护）到口育的进化转变为颅面系统引入了一种新功能，并提供了一个检验功能耦合假设的理想机会。通过结合几何形态测量学和最近开发的系统发育比较方法，我们发现，基质守护物种的头部形态进化速度比口育物种快43%。此外，对于雌性单独负责口育的物种，雄性头部形态的进化速度高于双亲共同口育的物种。我们的结果支持了这样一种假设，即导致功能耦合的适应性会限制表型进化。
