Arthropod parasites of marine mammals: convergent physical solutions of living on aquatic hosts

海洋哺乳动物感染了各种内寄生虫和外寄生虫，当它们不得不附着在宿主上时，这些寄生虫面临着多重挑战。海洋哺乳动物的节肢动物寄生虫已经形成了专门的解剖适应，以确保它们对水生宿主的控制，并制定了复杂的策略，使漂流的远洋和两栖野生动物之间能够传播。我们选择了三种不同适应海洋宿主的节肢动物：海豹虱，作为陆生的食血昆虫；鲸虱，作为海洋起源的端足类甲壳类动物；以及来自海豹呼吸道的呼吸道蠕虫。这三个物种都有活动的幼虫，这些幼虫在与宿主个体的身体接触中传播。它们的外骨骼通过调整材料和设计来进化，以生存在群居和潜水的海洋哺乳动物身上。人们对海洋哺乳动物节肢动物寄生虫的生物学知之甚少，更不了解它们在这个充满挑战的环境中生活的物理方面。需要新的方法来提供更多关于结构设计和机械性能的见解，以及关于其附着和运动的物理原理的知识。最先进的仪器，如Micro-CT、激光共聚焦扫描显微镜和低温扫描电子显微镜，将提供关于寄生虫形态适应的基本知识，使它们能够在潜水、拖出时附着在宿主上，以及它们如何承受电流和社会互动。比较昆虫、甲壳类和蜘蛛类不同生活史阶段在不同表面的运动能力和发育特征，以了解它们运动系统的功能形态。在寄生虫与寄主的交界处，寄生虫对寄主适合度的降低最为明显。鲸虱阻碍皮肤伤口的愈合过程，海豹虱是丝虫病和病毒性疾病的媒介。我们将利用感染组织的组织病理学来研究宿主-寄生虫的界面，以确定对宿主组织的结构性损害。用自制的微力测试装置研究了不同寄生虫物种所维持的摩擦力和粘附力。拟议的项目将提供关于选定节肢动物寄生虫物种中附着装置的结构、材料特性和附着性能之间的关系的知识。将首次研究它们的运动和招募动态的数据，其结果将为开发生物启发表面和专门用于增强或减少摩擦力或粘附力的系统提供新的途径。有关附件在不同个体发育阶段的特性及其在生命周期中的作用的新数据可能会揭示有趣的兽医方面。

Marine mammals are infected by a variety of endo- and ectoparasites which face multiple challenges when having to attach to their host. Arthropod parasites of marine mammals have developed specialized anatomical adaptations, to secure their hold on aquatic hosts, and sophisticated strategies to enable transmission between vagile pelagic and amphibious wildlife. We have chosen three arthropod species that have adapted differently to their marine hosts: seal lice, as hematophagous insects of terrestrial origin and whale lice, as amphipod crustaceans of marine origin, as well as respiratory mites from the airways of seals. All three species have motile larvae that are transmitted during bodily contact of host individuals. Their exoskeleton has evolved by adapting materials and design to survive on gregarious and diving marine mammals. Little is known about biology of marine mammal arthropod parasites, but even less about physical aspects of their life in this challenging environment. Novel approaches are required to provide more insight in structural design and mechanical properties and knowledge on physical principles of their attachment and locomotion. State of the art instrumentation, such as micro-CT, confocal laser scanning microscopy and Cryo-SEM will provide basic knowledge on morphological adaptations of parasites that enable their attachment to hosts during dives, haul-out and how they endure currents and social interactions. The locomotive abilities of the different life cycle stages on various surfaces and developed features of insect, crustacean and arachnid species are compared to understand functional morphology of their locomotory system. Parasites reduce the fitness of their host most obviously at the interface between parasite and host. Whale lice impede healing processes of skin wounds and seal lice are vectors for filarial and viral diseases. We will investigate the host-parasite interface using histopathology of infected tissues to define the structural damage to host tissues. Friction and adhesion forces maintained by the different parasite species are investigated by custom made microforce testing devices. The proposed project will provide knowledge on relationships between structure, material properties and attachment performance of attachment devices in selected arthropod parasite species. Data on their locomotion and recruitment dynamics will be studied for the first time and the results will provide new avenues for development of biologically-inspired surfaces and systems specialized for enhancement or reduction of frictional or adhesive forces. New data on the properties of attachment devices in different ontogenetic stages and their role in the life cycle can potentially reveal interesting veterinary aspects.