Tessier Alan J, Leibold Mathew A
W.K. Kellogg Biological Station and Department of Zoology, Michigan State University, Hickory Corners, MI 49060, USA fax: 616 671 2104; e-mail:
Department of Ecology and Evolution, University of Chicago, 1101 E. 57th Street, Chicago, IL 60637, USA, , , , , , US.
Oecologia. 1997 Feb;109(4):561-570. doi: 10.1007/s004420050117.
Many species of planktonic cladocerans display substantial variation in habitat use (mean depth and diel vertical migration), both among and within populations. We examined whether clonal segregation and specialization contributes to such behavioral variation within several lake populations of the cladoceran, Daphnia pulicaria. Electrophoretic and quantitative genetic analysis of clonal lines isolated from different depths at night revealed that clonal habitat specialization was common. Clones that utilized shallow water at night were genetically smaller at maturity and lower fecundity under standard laboratory conditions than the deep-water clones. The magnitude of this clonal habitat specialization varied among lakes: populations displaying broad use of depth habitats contained greater genetic variance than populations with more constrained habitat use. These results are consistent with known differences in selective factors in different depth habitats and suggest that substantial clonal specialization can occur within single populations. Since previous work has discovered a heritable basis to habitat selection in several Daphnia species, including D. pulicaria in our study lakes, it is likely that clonal/depth specialization is an important factor affecting the trophic ecology of Daphnia.
许多浮游性枝角类物种在栖息地利用（平均深度和昼夜垂直迁移）方面表现出显著差异，无论是在种群之间还是种群内部。我们研究了克隆分离和专业化是否导致了枝角类多刺裸腹溞几个湖泊种群内的这种行为差异。对夜间从不同深度分离出的克隆系进行电泳和数量遗传学分析，结果表明克隆栖息地专业化很常见。在标准实验室条件下，夜间利用浅水的克隆系在成熟时遗传上体型较小，繁殖力也低于深水克隆系。这种克隆栖息地专业化的程度在不同湖泊之间有所不同：与栖息地利用范围更有限的种群相比，显示出对深度栖息地广泛利用的种群具有更大的遗传变异。这些结果与不同深度栖息地选择因素的已知差异一致，并表明在单一种群内可能发生显著的克隆专业化。由于先前的研究已经发现了几种枝角类物种（包括我们研究湖泊中的多刺裸腹溞）栖息地选择的遗传基础，克隆/深度专业化很可能是影响枝角类营养生态学的一个重要因素。
