Rodríguez-González Abril, Míguez-Lozano Raúl, Llopis-Belenguer Cristina, Balbuena Juan Antonio
Marine Zoology Unit, Cavanilles Institute of Biodiversity and Evolutionary Biology, Science Park, University of Valencia, P.O. Box 22085, 46071 Valencia, Spain.
Marine Zoology Unit, Cavanilles Institute of Biodiversity and Evolutionary Biology, Science Park, University of Valencia, P.O. Box 22085, 46071 Valencia, Spain.
Int J Parasitol. 2015 Apr;45(5):295-303. doi: 10.1016/j.ijpara.2015.01.005. Epub 2015 Feb 28.
Evaluating phenotypic plasticity in attachment organs of parasites can provide information on the capacity to colonise new hosts and illuminate evolutionary processes driving host specificity. We analysed the variability in shape and size of the dorsal and ventral anchors of Ligophorus cephali from Mugil cephalus by means of geometric morphometrics and multivariate statistics. We also assessed the morphological integration between anchors and between the roots and points in order to gain insight into their functional morphology. Dorsal and ventral anchors showed a similar gradient of overall shape variation, but the amount of localised changes was much higher in the former. Statistical models describing variations in shape and size revealed clear differences between anchors. The dorsal anchor/bar complex seems more mobile than the ventral one in Ligophorus, and these differences may reflect different functional roles in attachment to the gills. The lower residual variation associated with the ventral anchor models suggests a tighter control of their shape and size, perhaps because these anchors seem to be responsible for firmer attachment and their size and shape would allow more effective responses to characteristics of the microenvironment within the individual host. Despite these putative functional differences, the high level of morphological integration indicates a concerted action between anchors. In addition, we found a slight, although significant, morphological integration between roots and points in both anchors, which suggests that a large fraction of the observed phenotypic variation does not compromise the functional role of anchors as levers. Given the low level of genetic variation in our sample, it is likely that much of the morphological variation reflects host-driven plastic responses. This supports the hypothesis of monogenean specificity through host-switching and rapid speciation. The present study demonstrates the potential of geometric morphometrics to provide new and previously unexplored insights into the functional morphology of attachment and evolutionary processes of host-parasite coevolution.
评估寄生虫附着器官的表型可塑性可以提供有关定殖新宿主能力的信息，并阐明驱动宿主特异性的进化过程。我们通过几何形态测量学和多元统计分析了来自鲻鱼的头盘虫背腹锚的形状和大小变异性。我们还评估了锚之间以及根部和尖端之间的形态整合，以便深入了解它们的功能形态。背腹锚显示出相似的整体形状变化梯度，但前者的局部变化量要高得多。描述形状和大小变化的统计模型揭示了锚之间的明显差异。在头盘虫中，背锚/杆复合体似乎比腹锚更具可动性，这些差异可能反映了在附着于鳃时的不同功能作用。与腹锚模型相关的较低残差变异表明对其形状和大小的控制更严格，也许是因为这些锚似乎负责更牢固的附着，并且它们的大小和形状将允许对个体宿主体内微环境特征做出更有效的反应。尽管存在这些假定的功能差异，但高度的形态整合表明锚之间存在协同作用。此外，我们发现两个锚的根部和尖端之间存在轻微但显著的形态整合迹象，这表明观察到的大部分表型变异不会损害锚作为杠杆的功能作用。鉴于我们样本中的遗传变异水平较低，很可能大部分形态变异反映了宿主驱动的可塑性反应。这支持了通过宿主转换和快速物种形成实现单殖吸虫特异性的假设。本研究证明了几何形态测量学在为附着功能形态和宿主 - 寄生虫协同进化的进化过程提供新的和以前未探索的见解方面的潜力。
