新疆盐湖卤虫寄生性绦虫区系调查及绦虫感染对卤虫繁殖策略的影响

Brine shrimps Artemia spp. (Branchiopoda, Anostraca) occurs in saline and hypersaline habitats are intermediate hosts for a rich community of avian cestodes. Early researches showed that Artemia swarming-surfacing propensity increased in cestode-infected hosts and that red colour intensity was higher in swarming compared with non-swarming infected hosts. These effects would result in increased cestode transmission to its final avian host. .Amidst the widespread threat of parasitism, hosts persist with the help of several lines of defence: anti-infection resistance, antigrowth resistance and tolerance mechanisms. In parasite-host systems, some parasite would castrate their hosts, while the hosts always show fecundity compensation and tolerance to sterilizing castratrion. In cestode-Artemia system, early studies showed the brine shrimps bearing cestode cysticercoids had host castration, but the mechanism of sterility tolerance still don’t know. As the host(Artemia) have two different reproductive mode (oviparity or diapause mode, and ovoviviparity or non-diapause mode), just based on if the host females “perceived” forthcoming environmental difficulties. It is obviously, the reproductive mode will have critical influence on the host (Artemia) fecundity and offsprings population development..This project will focus on if the cestodes infection will have influence on the host reproductive strategy and if the strategy change is a way to realize fecundity compensation..To realize the purpose, first we will survey the cestodes fauna of two salt lakes of Xinjiang by morphological method and molecular data (such as COI gene etc.), second we will comparative study the reproductive characteristics of the cestode-infective and uninfective Artemia population sampled from the two salt lakes of Xinjiang..The aim of the project are: to gain new data of cestodes fauna from Artemia of salt lakes in Xinjiang and gain better understanding of the mechanism of fecundity compensation of cestode-Artemia-avian systems in salt lakes.

绦虫-卤虫（中间宿主）-水鸟（终末宿主）是盐湖生境中独特的寄生系统。研究表明绦虫可以通过操控卤虫体色变红、产生表层集群行为等吸引鸟类来实现其最终进入终末宿主体内的目的。面对寄生，宿主同样产生了多种对抗和耐受机制。在寄生系统中，宿主通常会出现生殖阉割现象及多样的生殖补偿机制。卤虫的两种繁殖模式（非滞育和滞育）的选择主要受到母体对未来生境优劣预期的影响，优则卵胎生，劣则滞育卵生。在该寄生系统中卤虫具有生殖阉割现象但其生殖补偿机制未明。对此本项目拟以新疆卤虫主产区艾比湖、巴里坤盐湖卤虫寄生性绦虫为研究对象，通过野外调查、标本收集、种类鉴定(拟囊尾蚴形态学结合COI基因等DNA信息分析)，理清新疆盐湖卤虫寄生性绦虫的种类组成和区系特点；同时通过采集卤虫亚成体比较研究感染与未感染卤虫的繁殖模式（策略），揭示卤虫应对绦虫感染后的生殖补偿机制，为寄生系统宿主感染后生殖耐受和补偿机制多样性提供例证。

盐湖生态系统作为地球特殊的高盐生境，无论是生物资源还是绦虫-卤虫（中间宿主）-水鸟（终末宿主）构成的寄生系统都具有独特性。本项目通过对新疆各主要盐湖采样基本确定新疆各盐湖卤虫的寄生性绦虫囊尾蚴感染率低。收集建立了新疆各主要盐湖卤虫卵资源库将为新疆盐湖卤虫资源开发利用奠定基础。多季节采样获得了巴里坤盐湖浮游生物名录及相关图片，并与20世纪90年代数据进行群落结构分析，发现全球气候变化可能对盐湖群落结构产生了影响，浮游生物资源的获取将为开发利用盐湖生物资源尤其是微藻资源奠定基础，而浮游生物群落结构的变化分析将为盐湖调水管理提供一定的参考信息。测定了不同卵色卤虫卵显微结构及形态计量学差异，并确定与染色体倍性无关，卤虫卵色泽可能是一种遗传形状，孤雌卤虫可以稳定遗传，同一克隆种群其所有的繁殖胎次颜色一致，并且每一胎次不管卵的数量多少，均呈现一致的色泽。确定了巴里坤卤虫克隆种群滞育诱导关键期。卤虫卵色的遗传特性和滞育诱导关键期的确定对卤虫人工养殖和种质选育具有一定的参考价值。记录了巴里坤盐湖卤虫出现的卤虫第三种畸形结构。记录新疆盐湖水蝇属一中国新记录种，测定了其线粒体基因组全序列，丰富了我国盐湖生物多样性记录。