黑腹胃蝇持续重度感染放归普氏野马机制研究

After the reintroduction to their ancestral home of Junggar Basin, Przewalski's horse (Equus przewalskii) have been seriously infected by Gasterophilus spp. The infection degree of Gasterophilus spp. is greater in Przewalski's horse than in Mongolian wild asses which live in the same area. Previous study has shown that the high prevalence, the large number of infection, the variety of species and especially G. pecorum as the predominate species are the key characteristics of Gasterophilus spp. According to this situation, the parasite administration is performed annually during the winter for Przewalski's horse to maintain their fitness. However, this work is an extremely serious constraint on the re-wilding process. Based on the ten-year conservation practice of Przewalski's horse, this study will do further exploration on the mechanism of the continuous and severe infection in Przewalski's horse by G. pecorum. We use the classic ecological methods and geostatistical technology to study the “G. pecorum – pasture – wild equids” interactions in fields of biology and phenology. The research includes: the life history and the population dynamics of G. pecorum in vitro of host, the species of pasture as ovipositional substrates and the spatiotemporal dynamics of areas infected by G. pecorum’s eggs, etc. Through above studies, we will analyze the mechanism of the severe infection in Przewalski's horse by G. pecorum and explain why G. pecorum was the dominate species of Gasterophilus spp. in desert steppe. Research findings will not only have the conservation biological value, but also have theoretical and practical significance in reintroduced species’ parasite ecology.

重引入物种普氏野马放归到祖居地准噶尔盆地后暴露出严重的马胃蝇感染问题，其程度超过同域蒙古野驴。前期研究表明：该地区马胃蝇的发生以宿主感染率高、感染数量大、种类多，特别是以黑腹胃蝇为显著优势种为特点，以致每年定期给野马进行保健性驱虫，严重制约了普氏野马野化进程。本项目以长达十年的野马保护实践和研究为基础，针对黑腹胃蝇持续、严重感染普氏野马的机制开展初期研究。项目采用经典的生态学方法和地统学技术，围绕“黑腹胃蝇—牧草—野生马科动物”关系系统开展相关物种生物学、物候学研究。具体研究内容包括：黑腹胃蝇宿主体外生活史及种群动态、作为产卵基质的牧草种类以及疫区时空动态等，以此开展黑腹胃蝇重度感染普氏野马机制的探索，为解析黑腹胃蝇在干旱荒漠草原优势发生的成因奠定基础。本项目既具有保护生物学价值，也具有再引入物种寄生虫生态学研究的理论与实践意义。

重引入物种普氏野马放归到祖居地准噶尔盆地后暴露出严重的马胃蝇感染问题，其感染程度超过同域蒙古野驴。前期研究表明：该地区马胃蝇的发生以宿主感染率高、感染数量大、种类多，特别是以黑腹胃蝇为显著优势种为特点，以致每年定期给野马进行保健性驱虫，严重制约了普氏野马野化进程。本项目以长达十年的野马保护实践和研究为基础，针对黑腹胃蝇持续、严重感染普氏野马的机制开展进一步探索。项目采用经典的生态学方法和地统学技术，围绕“黑腹胃蝇—牧草—野生马科动物”关系系统开展相关物种生物学、物候学、行为学研究。具体研究内容包括：黑腹胃蝇宿主体外生活史及种群动态、作为产卵基质的牧草种类、疫区时空动态等。研究结果显示，黑腹胃蝇雌蝇通过提高怀卵量，降低单次产卵数量，以分散产卵的方式增加了感染宿主的几率，对荒漠草原有了新的适应，其独特的繁殖特性对当地生态系统的适应是持续重度感染放归普氏野马的重要原因。水源地作为当地野生动物频繁交汇重要区域，不仅是马科动物的生存平台，同时也成为保护区内黑腹胃蝇传播及感染最主要的场所。对此，未来保护工作应重视区域内野生动物水资源分配，通过人工改造和新增水源，或在胃蝇幼虫排出高峰后隔离出核心感染疫区等措施，有效控制普氏野马黑腹胃蝇蛆病感染源，并降低野马感染黑腹胃蝇几率，使其重归之旅平坦顺利。