近缘种间的性信号很相似，同域分布时性信号分化增强, 使配偶识别准确。过去针对性信息素的生殖性状位移的研究仅蝶类一例报道。鼠类主要依靠信息素通讯。北方褐家鼠种群长期缺乏近缘种竞争，但是最近30年，其近缘种黄胸鼠显著向北方扩展。我们利用黄胸鼠的生态入侵这个现象， 探索黄胸鼠和褐家鼠同域分布对信息素性状位移的影响，具体包括（1）北扩黄胸鼠种群的来源或路径及种群遗传多样性的变化；（2）褐家鼠在与黄胸鼠古老同域分布区、新的分布区和异域分布区遗传多样性变化；(3) 种间的行为互作、嗅觉识别、信息素组成与两个近缘鼠种的共存和竞争的关系及生理基础（近因）；(4) 化学通讯调节的黄胸鼠和褐家鼠的配偶选择对种间信息素分化的影响和可能的遗传基础。旨在阐明黄胸鼠和褐家鼠的竞争与性信息素分化和种间行为生殖隔离形成的过程及进化特点。本项目拟发表4-6篇英文论文，培养4-6名研究生和博士后。

The sexual signals between closely related species are highly similar, however, when they are sympatric, the divergences between the signals are enforced for right mate choice. Only a study case of sex pheromone character diaplacement has been recently reported in butterflies. Such studies have been never attempted in rodents that mainly rely on pheromonal communication in most behavioral contexts. The populations of brown rats in north China have been allopatric for a long time, however, in the last 30 years, their closely related species, Asian house rats, showed a striking northward rang expasion. Therefore, using the invasion process, we plan to explore the sympatric effects of the rats on sex pheromone character displacement and the underlying mechanisms， including (1) the sources and genetic diversity of invasive Asian house rats ; (2) comparision of the genetic diversity of rown rat populations across sympatric and allopatric areas;(3) how behavioral interactions, olfactory recognition and sex pheromone components to be affected by coexistence and competition of these two rats species and the underlying physiological mehcanisms (immediate cause); (4) Effects of chemical communication-based mate preferences on the divergences of sex and species pheromones and their genetic basis. Four to six papers in English are expected to be published , and 4-6 postgratitutes and postdoctors will be trained with the supports from the grant.