Ciros-Pérez Jorge, Carmona María, Serra Manuel
Institut Cavanilles de Biodiversitat i Biologia Evolutiva, Universitat de València, A. O. 22085, València, 46071, Spain.
Oecologia. 2002 Mar;131(1):35-42. doi: 10.1007/s00442-001-0856-6. Epub 2002 Mar 1.
We present experimental data on the reproduction patterns of three sympatric sibling rotifer species, belonging to the Brachionus plicatilis complex, as they compete for food. Variation existed in the amount and pattern of sexual reproduction among the three cyclical parthenogenetic species. Competitive exclusion between the three Brachionus species was related to a higher investment in sexual reproduction by the inferior competitor. In general, no correlation was found between sexual reproduction and population density in a given species. However, when pairs of competing species were compared, a negative relationship between sexual investment differences (between species) and average population density differences was frequently found. From the results we conclude that: (1) the characteristic sexual pattern of each species has some implications for the competitive outcome; (2) allocation of resources into sexual reproduction does not mediate coexistence; and (3) the response of sexual reproduction to competitive interaction is unlikely to determine competition outcome. Nevertheless, our results suggest that the competitively inferior species invests more in sexual reproduction, as a response to resource limitation, which would accelerate its exclusion.
我们展示了属于褶皱臂尾轮虫复合体的三种同域共存的姐妹轮虫物种在争夺食物时的繁殖模式的实验数据。这三种周期性孤雌生殖物种的有性生殖数量和模式存在差异。三种臂尾轮虫物种之间的竞争排斥与劣势竞争者在有性生殖方面的更高投入有关。一般来说，在给定物种中，未发现有性生殖与种群密度之间存在相关性。然而，当比较竞争物种对时，经常会发现（物种间的）有性投入差异与平均种群密度差异之间呈负相关。从结果中我们得出以下结论：（1）每个物种的特征性有性模式对竞争结果有一定影响；（2）资源分配到有性生殖中并不能调节共存；（3）有性生殖对竞争相互作用的反应不太可能决定竞争结果。尽管如此，我们的结果表明，作为对资源限制的一种反应，竞争劣势物种在有性生殖方面投入更多，这将加速其被排斥。
