Pheromone blend complexity in heliothine moths

昆虫，尤其是飞蛾，严重依赖性信息素，作为一种基于气味的交流手段，将异性聚集在一起。到目前为止，成千上万的性信息素已经被识别出来，每个物种都有自己独特的化学混合物来吸引配偶(通常是由雌性产生以吸引同一物种的雄性)。因此，信息素的组成有令人难以置信的多样性，但随着新物种的进化和彼此分化，人们对这些化学物质的进化和生产、检测和偏好的变化缺乏了解。这就引出了一个问题，“为什么会有这么多独特的信息素混合物？”尽管昆虫中记录了丰富的信息素，但科学仍在努力了解信息素组成和偏好在物种形成事件(新物种的形成)期间发生变化的机制，或者这些特征是否实际上可能推动物种形成。了解这种变化对于我们理解嗅觉系统的功能是至关重要的，而且对于采用使用信息素来监测和控制害虫的昆虫控制策略也是至关重要的。该项目将在生殖物种隔离的背景下研究信息素偏好，以及相关物种间信息素检测和处理的神经生理学相关性。通过比较亲缘关系密切的物种，向日葵蛾是检验信息素产生的差异性以及检测和处理机制的一个很好的模式系统。具体地说，根据每一物种性信息素混合物中关键成分的使用变化，在日光甘草属物种之间的嗅觉交流方面存在明显的差异。这些混合体的功能既能吸引同一物种的成员，又能抑制近缘物种之间的交配错误。例如，吸引雄性同种的雌性信息素成分可能对其他密切相关物种的雄性具有强烈的拮抗作用。在信息素组成的研究中，8种蛾将被检测，并测试行为混合偏好，以及受体表达和调节这种偏好的神经生理机制。通过使用结合了化学、生理学和分子生物学的多方面、综合的方法，我们将显著地建立在基于信息素的物种分离和基本嗅觉处理的进化的现有知识的基础上。通过探索与信息素变化相对应的假定神经机制，我们可以理解信息素混合时的复杂性。通过更好地了解信息素的演变，我们将能够为许多物种开发对环境负责的昆虫管理技术，从而确保加拿大人的健康以及农业和自然资源的可持续性。

Insects, and particularly moths, rely heavily on sex pheromones as a means of odor-based communication to draw together opposite sexes. To date, thousands of sex pheromones have been identified, with each species having its own unique blend of chemicals which will attract a mate (typically produced by females to attract males of the same species). As such, there is incredible diversity in pheromone composition, but a poor understanding of the evolution and shifts in production, detection and preference of these chemicals as new species evolve and diverge from one another. This begs the question, “why are there so many unique pheromone blends?” Despite the wealth of documented pheromones in insects, science is still struggling to understand the mechanisms by which pheromone composition and preferences shift during speciation events (formation of new species), or if these features may, in fact, drive speciation. Understanding such shifts are paramount to our understanding of olfactory system function, and moreover, to adapting insect control strategies which use pheromones to monitor and control pests. This project will examine pheromone preference in the context of reproductive species isolation, along with neurophysiological correlates of pheromone detection and processing across related species of heliothine moths. Heliothine moths represent an excellent model system for examining divergence of pheromone production, and the mechanisms of detection and processing, by comparing closely related species. Specifically, divergence in olfactory communication is evident among heliothine species, based on shifts in the use of key components within each species' sex pheromone blend. These blends function to both attract members of the same species, and inhibit mating errors between closely related species. For example, a female sex pheromone component attractive to male conspecifics may be strongly antagonistic to males of other, closely related species. Eight species of moths will be examined in studies of pheromone composition, and tested for behavioral blend preference, along with receptor expression and neurophysiological mechanisms modulating such preference.By using a multi-faceted, integrated approach, which incorporates chemistry, physiology and molecular biology, we will build significantly upon the current knowledge of the evolution of pheromone-based species isolation, and basic olfactory processing. By exploring putative neural mechanisms which correspond with changes in pheromones, we can understand how complexity if selected for in pheromone blends. Through a better understanding of pheromone evolution, we will enable development of environmentally responsible insect management technologies for many species, thereby ensuring the health of Canadians and sustainability of agriculture and natural resources.