Kaufmann Joshka, Eizaguirre Christophe, Milinski Manfred, Lenz Tobias L
Department of Evolutionary Ecology, Max Planck Institute for Evolutionary Biology, Plön, Germany
GEOMAR Helmholtz Centre for Ocean Research, Kiel, Germany School of Biological and Chemical Sciences, Queen Mary University of London, London, UK.
Biol Lett. 2015 Jan;11(1):20140933. doi: 10.1098/rsbl.2014.0933.
Ecology can play a major role in species diversification. As individuals are adapting to contrasting habitats, reproductive barriers may evolve at multiple levels. While pre-mating barriers have been extensively studied, the evolution of post-mating reproductive isolation during early stages of ecological speciation remains poorly understood. In diverging three-spined stickleback ecotypes from two lakes and two rivers, we observed differences in sperm traits between lake and river males. Interestingly, these differences did not translate into ecotype-specific gamete precedence for sympatric males in competitive in vitro fertilization experiments, potentially owing to antagonistic compensatory effects. However, we observed indirect evidence for impeded development of inter-ecotype zygotes, possibly suggesting an early stage of genetic incompatibility between ecotypes. Our results show that pre-zygotic post-copulatory mechanisms play a minor role during this first stage of ecotype divergence, but suggest that genetic incompatibilities may arise at early stages of ecological speciation.
生态学在物种多样化过程中可能发挥重要作用。随着个体适应不同的栖息地，生殖隔离可能在多个层面上演变。虽然交配前的隔离已得到广泛研究，但在生态物种形成早期阶段交配后的生殖隔离的进化仍知之甚少。在来自两个湖泊和两条河流的分化三刺鱼生态型中，我们观察到湖泊和河流雄性个体在精子特征上存在差异。有趣的是，在体外受精竞争实验中，这些差异并未转化为同域雄性个体的生态型特异性配子优先性，这可能是由于拮抗补偿效应。然而，我们观察到生态型间合子发育受阻的间接证据，这可能表明生态型之间存在遗传不相容的早期阶段。我们的结果表明，交配后合子前机制在生态型分化的第一阶段作用较小，但表明遗传不相容可能在生态物种形成的早期阶段出现。
