以蜜露为纽带，蚂蚁与排泄蜜露的蚜虫在漫长的进化过程中逐渐形成了复杂而密切的关系。蚂蚁能促进蚜虫取食，保护蚜虫不受天敌和致病菌的攻击，同时蚜虫为蚂蚁提供蜜露。蚂蚁也会给蚜虫带来不利的影响，如蚜虫个体变小、产仔量减少，扩散活动受限，有翅蚜的产生受抑制等。本研究以我国重要的农业害虫棉蚜和入侵我国南方的红火蚁为实验材料，研究红火蚁和棉蚜（存在兼性共生关系）之间的相互关系，分析共生红火蚁对棉蚜的翅型分化的影响；鉴定共生红火蚁抑制棉蚜翅型分化的信息化合物的结构，并进行化学合成；利用转录组技术鉴定棉蚜感受红火蚁活性化合物的气味结合蛋白（OBP）、化学感受蛋白（CSP）和气味受体（OR）基因；利用RNA干扰技术验证所筛选的关键嗅觉基因的功能。本项目的研究结果将有助于阐明蚜-蚁共生的化学和分子机制。

Honeydew plays a very important role in the development of close and sophisticated mutualistic relationship between ants (Hymenoptera: Formicidae) and some aphid speices (Hemiptera: Sternorrhyncha, previously Homoptera) over the long evolutionary history. Aphids offer sugary-rich honeydew to the ants, which, in exchange, enchance aphid feeding activities and protect the aphids against natural enemies and lethal pathogens. At the same time though, increased ant attendance caused by the production of more or better quality honeydew can also be costly. For instance, the costs can result in slow development, low fecundity, limited dispersal, decreased production rate of winged forms.In this proposal, the important agricultural pest, cotton aphid (Aphis gossypii, genome sequencing completed) which is a facultative ant-tended species, and a recently introduced ant speceis, the red imported fire ant (Solenopsis invicta) that can develop mutulistic relationshop with cotton aphids in cotton field are selected to serve as model insects to study ant-aphid interactions. This proposal aims to study: 1) the influence of fire ant attendance on reproduction, and wing polyphenism of cotton aphid; 2) identification and synthesis of semiochemicals released by ants to impact on the behavior and wing polyphenism of aphids; 3) identification of odorant binding protein (OBP), chemosensory protein (CSP), and odorant receptor (OR) genes involved in the olfaction of identified semiochemicals released by fire ant workers by transcriptome technique; 4) functional confirmation of 1-3 selected OBP, CSP, and OR genes via RNA interference technique. The outcome of this proposal will facilitate our understanding of the chemically mediated mechanism in the ant-aphid mutualism.