汀棠湖萼花臂尾轮虫姊妹种组成和生活史特征的时间变化  

Temporal variation in composition of Brachionus calyciflorus complex and life history traits of sibling species in Lake Tingtang

作　　者：李瑶[1] 席贻龙[1] 王爱民[1] 牛翔翔 温新利[1] 刘桂云[1] 

机构地区：[1]安徽师范大学生命科学学院,安徽省高校生物环境与生态安全省级重点实验室,芜湖241000

出　　处：《生态学报》2014年第21期6172-6181,共10页Acta Ecologica Sinica

基　　金：国家自然科学基金(31170395);教育部博士点基金(20093424110002);安徽省高校生物环境与生态安全省级重点实验室专项基金;重要生物资源保护和利用研究安徽省重点实验室专项基金

摘　　要：于2011年7月对汀棠湖水体中的萼花臂尾轮虫(Brachionus calyciflorus)进行了每周1次的采集、实验室克隆培养、DNA提取、COI基因扩增、序列测定和分析,研究了萼花臂尾轮虫种复合体结构的时间变化;参照采样期间自然水温的波动范围(28—32℃)和处于轻度富营养状态的汀棠湖水体中藻类和有机碎屑等的丰富程度,选择了在28℃和32℃等2个温度以及1.0×106、3.0×106和5.0×106个细胞/m L等3个较高的斜生栅藻(Scenedesmus obliquus)密度下研究了轮虫姊妹种生命表统计学参数(包括生命期望、平均寿命、世代时间、净生殖率、种群内禀增长率和后代混交率)的时间变化。结果表明,59条序列共定义了38个单倍型,系统发生分析将38个单倍型分为2个支系,2支系间的COI基因序列差异百分比为13.9%—15.6%,2支系应为2个姊妹种(姊妹种T1和姊妹种T2)。姊妹种T1的相对丰度由第1采集批次向第3采集批次快速降低,至第4采集批次时从水体中消失;与此相反,姊妹种T2的相对丰度却随着时间的推移而逐渐升高,但8月初从水体中消失。姊妹种T1各生命表统计学参数以及姊妹种T2的世代时间、净生殖率、内禀增长率和后代混交率均随着采集批次的增加而发生显著的变化。在较低(<20个/L)的种复合体密度下,两姊妹种之间不会因为食物或空间资源等产生竞争;两姊妹种在种群内禀增长率等主要适合度参数之间的无显著性差异(P>0.05)是它们能够共存于汀棠湖水体中的另一主要原因。而姊妹种T1和姊妹种T2在7月29日和8月5日依次从水体中消失则与它们在1周前的净生殖率和种群内禀增长率等显著降低(P<0.05)有关。消失时间上的差异可能在于姊妹种T1的所有生命表统计学参数均不受温度的显著影响(P>0.05),而姊妹种T2的所有生命表统计学参数均随着温度的升高而显著地增大(P<0.05)。Despite their high morphological similarity,sibling species often coexist in aquatic habitats presenting a challenge in the framework of niche differentiation theory and coexistence mechanisms.Here Brachionus calyciorus species complex inhabiting Lake Tingtang,a shallow eutrophic lake,was used to gain insights into the mechanisms involved in coexistence in sibling species.The animals were collected once a week from Lake Tingtang in July 2011,when the water temperature increased from 28℃ to 32℃.Then the animals were clonally cultured in lab,and their COI genes were sequenced and analyzed to reconstruct the coexistence dynamics of sibling species.Forty-seven rotifer clones from fourcollections and two sibling species were used to calculate their life table demographic parameters including life expectancy at hatching,average lifespan,generation time,net reproduction rate,intrinsic rate of population increase and the proportion of sexual offspring at 28℃ and 32℃,and with 1.0 × 106,3.0 × 106 and 5.0 × 106 cells / ml of Scenedesmus obliquus as their food,and the responses in the life table demographic parameters to water temperature,algal density and collection batch were analyzed to explore the coexistence mechanisms.In total of 59 samples,38 haplotypes were defined,among which 2 distinct lineages（ Lineages Ⅰ and Ⅱ） were revealed by phylogenetic analysis.Sequence divergence was 13.9% —15.6% between the two lineages,indicating the occurrence of two sibling species（ sibling species T1 and sibling species T2）.The relative abundance of sibling species T1 in the density of the species complex decreased rapidly from the first collection to the third collection;and in the fourth collection,the sibling species disappeared from the water body.However,the relative abundance of sibling species T2 increased from the first collection to the fourth collection;and after a week,the sibling species also disappeared from the water body.All the life table demographic parameters of sibling species T1,and the g

关 键 词：萼花臂尾轮虫 姊妹种 温度 食物密度 生活史特征 时间变化 

分 类 号：Q958[生物学—动物学]