基于生物矿化研究福寿螺性二型的形成机制及其适应意义

The invasion of the apple snail Pomacea canaliculata into China, harms to the agriculture, ecological safety and public health. Super fecundity, one of the fundamental reasons, made this invasive snail to be global pests. Optimization of the energy configuration is responsible for the highly efficient propagation. Sexual dimorphism, which comes from the evolution of sexual selection and environmental adaptation, marks the optimization of the energy configuration in snail populations. Therefore, it is greatly important to study the formation mechanism of the sexual dimorphism if we want to reveal the causes of the high fecundity. Additionally, the sexual dimorphism always embodied in the shell morphology, and the formation and growth of the shell is a biomineralization process. So, the shell mineralization and growth are to be comparatively studied through biomineralization method. And a special focus is taken to the differences of mineralization regulation during the development of the sexualdimorphism. Furthermore, two snail populations with different shell morphology of size and thickness will be constructed in chemical ecology according to our previous work, and then a research of “shell morphology - parental investment - reproductive efficiency” are carried out in productive behavioral ecology. Finally, the spatial variation of the shell is tested in large scale, and then using collected eggs as an addition, the genetic differentiation is determined by common garden experiment. Comprehensively analyzed, we will clarify the formation process of sexual dimorphism and its adaptation to nature. The results will further expand and improve the theory of hazard mechanism of the worst invasive snail.

福寿螺的入侵严重危害我国的农业、生态和公共卫生安全，高繁殖力是其暴发成灾的主因之一。高效繁殖来自于种群能量的优化配置，而性二型是性选择和环境适应的进化结果，是能量优化配置的体现。因此研究福寿螺性二型的形成机制是揭示其高繁殖力成因的关键。福寿螺的性二型集中体现在壳形上，而贝壳的形成与生长是一个生物矿化过程。因此，本研究应用生物矿化学方法比较研究两性螺壳的矿化成核机制和结构生长规律，并着重研究性二型发育期的矿化调控差异。在此基础上，利用化学生态学方法构建壳体型和厚度差异的模型螺，并采用繁殖行为生态学方法，研究性二型、亲本投资和繁殖效率三者的相关性。最后，在野外大尺度上检验性二型的空间变异，同时通过同质园实验测定性二型的遗传分化，综合分析性二型的形成过程及其适应意义。本项目的研究结果将进一步丰富和完善福寿螺的成灾机制理论。

福寿螺是危害最大的入侵性水生动物，严重危害农业生产、威胁生态系统健康和公共卫生安全，其种群如何通过能量配置是研究其实现高繁殖力的关键。研究表明福寿螺壳的生长是一个受到自身行为和外界环境影响的连续过程；雄螺突出的外壳具有竞争性优势，而轻薄外壳具有低能耗优势；贝类的壳体质量比具有较强的种属特异性，陆生贝类显著小于水生贝类，福寿螺的壳体质量比约为0.5，但是气囊结构抵消掉了这一劣势；福寿螺的耐酸性随发育期不同呈先升高后降低的抛物线形；雌雄福寿螺抗氧化酶含量差异显著，雄螺抗氧化反应剧烈、损伤较大，雌螺抗性较强；食物类型对不同发育期福寿螺纤维素酶、淀粉酶活性的影响极显著，且与壳高的交互作用极显著。因此，福寿螺种群的高增长率可能是通过雌雄性二型和生活史两因素驱动的综合优化能量配置实现的。