Diversification, adaptation and speciation in a temperate frog

尽管半个多世纪以来，我们对物种形成机制的理解取得了令人难以置信的进步，但仍然存在悬而未决的问题。特别是，我们缺乏关于地理和时间序列的全面信息，这些信息是关于在整个单一物种范围内，进化谱系之间（物种形成的标志）交配障碍的进化。冰川作用导致的分布区破碎化，最终是如何影响生殖隔离屏障的进化的？在长的分离谱系接触后，对杂交的选择是否增强了交配偏好的差异，这一过程被称为强化？在不同的生态选择和有限的扩散情景下，交配系统，特别是繁殖物候（繁殖活动的顺序）的差异会在细尺度上出现吗？我们解决这些问题，使用遗传和实验研究的一个小北美青蛙，春天偷窥。在我们的第一个项目中，我们确定了整个物种范围内不同对谱系之间的主要次级接触区，并将测试（1）谱系之间配偶识别系统的关键差异，（2）男性呼叫和女性偏好差异的遗传基础，（3）杂交后代遗传不相容的证据，以及（4）次级强化的证据。我们的第二个项目将研究可能导致这种差异的生态机制。特别是在一个环境异质2500平方米。公里.在东部安大略地区，我们将测试是否选择压力在不同的植被结构和小气候的栖息地可以产生显着差异（1）春季出现和男性的呼叫时间，（2）男性广告呼叫的声学特性。结合这些项目的见解，将推进我们的知识之间的相互作用，地理隔离，接触区动态，物种形成的生态选择。我们的研究结果共同说明了气候变化是如何以及在未来如何改变进化轨迹的。这项研究为至少44名学生提供了进化生态学方面的特殊培训。

Despite over a half-century of incredible advances in our understanding of speciation mechanisms, there remain outstanding issues. In particular we lack comprehensive information on the geography and temporal sequence for the evolution of barriers to mating between evolutionary lineages [the hallmarks of speciation] across the entire range of single species. How has range fragmentation, precipitated by glaciations, ultimately impacted the evolution of reproductive isolating barriers? Does selection against hybridization after contact of long sundered lineages enhance differences in mating preferences, a process called reinforcement? Can differences in the mating system, particular breeding phenology (sequence of breeding activities), arise at fine scales under divergent ecological selection and restricted dispersal scenarios? We address these questions using genetic and experiment studies of a small North American frog, the spring peeper. For our first project, we identified major secondary contact zones between different pairs of lineages throughout the species' range, and will test for (1) key differences in the mate recognition system between lineages, (2) the genetic basis for male call and female preference differences for them, (3) evidence for genetic incompatibilities in hybrids, and (4) evidence for secondary reinforcement. Our second project will examine the ecological mechanisms that may cause such divergence. Specifically within an environmentally heterogeneous 2500 sq. km. area in Eastern Ontario, we will test whether selection pressures in habitats differing in vegetation structure and microclimate can produce significant differences in (1) spring emergence and calling times of males, and (2) the acoustic properties of male advertisement calls. Combined insights from these projects will advance our knowledge of the interplay among, geographical isolation, contact zone dynamics, and ecological selection in speciation. Together our results speak to how climate change has and can in the future alter evolutionary trajectories. The research provides exceptional training in evolutionary ecology for a minimum of 44 students.