花食物报酬对传粉蝇类访花行为的影响和调控机制

传粉过程是自然生态系统到人为管理农业生态系统维持和可持续性发展的关键环节，花部食物报酬则是连接植物与传粉者的关键枢纽和核心。但花部食物报酬，特别是食物报酬的营养价值对传粉者传粉行为的直接影响及其机制等方面的研究却极少，从而阻碍了人们对植物与传粉者之间协同进化的深入探讨和理解。本项目拟以兰科石豆兰属中唇瓣具有糖类分泌物和蛋白质分泌物的植物为研究体系，借助模式生物黑腹果蝇的优势，率先开展传粉果蝇中内生感官系统对糖类和蛋白质类食物信号的响应式样，探讨食物报酬以及食物营养价值信号介导的相关内生信号和由外部花气味介导的外周感官信号协同调控作用式样和机制，揭示传粉者传粉行为决策的规律及机理。研究结果将为全面理解植物与传粉者协同进化关系提供新的视野。同时，可以为生物防治有害昆虫，以及构建人为调控传粉者在特定时间为特定经济作物传粉的体系从而解决全球农业生态系统传粉者不足等方面提供新的策略和思路。

Pollination process is a crucial service for the maintenance and sustainability of natural and agricultural terrestrial ecosystems. The floral food rewards are the key connecting node between plants and pollinators. Pollinators do the pollinating works while they feed the floral food rewards from the flowers. Previous studies showed that pollinating behavior as well as feeding behavior of pollinators are independently regulated by neuromodulatory signals. Those signals include olfactory and visual signals mediating attraction to food resources, and the signals of food sources, such as taste valence, nutrient value and textual features, permitting actual food intake. However, how the food signals be received and transduced by the peripheral nervous system of the pollinators during visiting flowers, and how they influence the pollinating behaviors are poorly understood, and it hinders our extensive understanding the co-evolution relationship between pollinators and plants. There is nectar-rich food-rewards in longitudinal labellar groove of different Bulbophyllum species, but the protein-rich food-rewards only occurs in the section of Racemosae of this genus. Surprisingly, we found one new species from Yunnan, China, in the section of Racemosae has nectar-rich food-rewards in the labellar groove. In fact, this new species is misidentified as Bulbophyllum crassipes in the section Racemosae by the taxonomists, which is the species with typical protein-rich food rewards in the labellar groove according our previously observation. More interestingly, accompanying with the changes of nectar-rich food-rewards of species outsides Racemosae section to protein-rich food-rewards of species in Racemosae section, the pollinators shift from Bactrocera of Tephritidae to Drosophila of Drosophilidae. However, within the section Racemosae, accompanying with similar changes are different species of Drosophila as pollinators. Therefore, we speculated that the signals of food-rewards perhaps play a key role in the shifts of different Drosophila pollinators between protein-rich food-rewards species and nectar-rich food-rewards species within the section Racemosae, and the floral odor signals, or co-operation of floral odor signals and food-rewards signals play a key role in the shifts of Bactorcera and Drosophila pollinators among the species from outsides and within Racemosae section. Our project plans to study the Drosophila and Bactorcera pollination system in the genus Bulbophyllum. In the model organisms Drosophila melanogaster, there are great progress in understanding neuromodulation in the feeding behavior of adult flies. The model fruit fly shares the basic metabolic regulation that is conserved throughout evolution with other Drosophila pollinators, so as a simple genetic model it will provide reliable insights to advance the studies in more complex pollinating behaviors of Drosophila pollinators. Taking the advantages of the model fruit fly in neural biology and genetics, we will focus on the neural processing of the different orchid food signals in the Drosophila pollinators, and the interaction between food signals and pollinating behavior. Furthermore, we will explore the potential mechanisms of floral odor signals co-operating with the food signals on pollinating behavior. The study of those interactions will deliver new insights into the pollinating behavior features and neural mechanisms of pollinators in coevolution process of plants and animals. The improvement of these basic theory and knowledge of pollination biology from our study can contribute to manipulate and modify the activity of neurons in central brain of pollinator by altering the pollinators to different odors and different food types to achieve higher pollination efficiency, as a new strategy to buffer the global insufficiency of pollination services in ecosystems and agricultural systems.