互利共生关系下红火蚁对扶桑绵粉蚧的化学识别机制

Both of Solenopsis invicta and Phenacoccus solenopsis are two important and newly invading insects in China. The stable mutualistic interaction of two insects has been set up after mutual adaption and facilitation in the infestation regions of South China. Consequently two invasive species have spread rapidly and broke out all over Southern China's provinces, resulting in serious economic loss and ecological disaster. The recognition of mealybug by tending ants is usually critical to the mutualistic relationship between ants and honeydew-producing mealybug, but until now chemical cues that elicit ant recognition on mealybug is unclear. Therefore, we hypothesize that some volatile compounds from mealybug body and honeydew induce the recognition of mealybugs by ants. In our study, we will test our hypothesis using fire ant S. invicta and cotton mealybug P. solenopsis. Our study will include the following three objectives: (1) Analyze volatiles of mealybug bodies and honeydew, and cuticular hydrocarbons. (2) Determine active components for fire ants from above three sources by using GC-EAD and Y-tube olfactometer. (3) Determine the chemicals for recognition of mealybug by fire ants by using aggression bioassays. We will clarify chemical cues for fire ants recognition on cotton mealybug, providing an evidence for exploring chemical recognition between ants and mealybugs as a mutualistic partner, and insight for the role of chemical cues in quarantine and prevention of alien invasive species.

在入侵区域，红火蚁已与扶桑绵粉蚧形成了普遍的互利共生关系，进而产生两入侵物种的相互促进效应，致使二者在我国南方多省迅速蔓延并暴发成灾，造成了严重的经济损失和生态灾难。红火蚁对扶桑绵粉蚧的准确识别是二者互利共生关系形成的关键，但其化学识别机制尚不明确。鉴于此，本项目以红火蚁和扶桑绵粉蚧为研究对象，采用行为学、电生理学、化学生态学的研究方法，重点研究：1）提取、分离并鉴定扶桑绵粉蚧蜜露挥发物、体表挥发物及表皮碳氢化合物的主要成分；2）从上述化合物中筛选引起红火蚁生理反应的活性成分；3）红火蚁对活性成分的识别功能验证，判定红火蚁识别扶桑绵粉蚧过程中主要利用的信息化合物。项目研究结果将阐明互利共生关系下红火蚁对扶桑绵粉蚧的化学识别机制，为探明蚂蚁与粉蚧类产蜜昆虫的互作机制及化学识别机制提供依据，为互利共生关系下外来入侵生物的检疫与防控提供新思路。

蚂蚁与半翅目产蜜昆虫的互惠互利是常见的生态学现象，在生态系统中发挥着十分重要的作用，而入侵蚂蚁参与的这种互利共生关系成为近年入侵生物学的研究热点之一。本研究以红火蚁和扶桑绵粉蚧为研究对象，从行为学、电生理学、化学生态学等角度研究入侵蚂蚁与入侵粉蚧之间的互利共生关系，获得如下研究结果：（1）鉴定明确了月桂酸甘油酯和豆蔻酸甘油酯、棕榈酸分别是扶桑绵粉蚧体表挥发物和蜜露挥发物的主要成分，但红火蚁工蚁未对这些挥发性成分表现出明显的偏好性；（2）研究明确了扶桑绵粉蚧虫体和蜜露均对红火蚁工蚁具有一定的吸引作用，蜜露的吸引作用明显较强，与虫体相比，蜜露是吸引红火蚁工蚁前来取食的重要因素；（3）通过红火蚁对糖类成分的偏好性研究，明确了工蚁取食糖先嗅觉、后味觉的行为谱，证实了前足跗节和触角是感受糖类化合物的主要器官，并揭示了前足附节Chaetic和触角Basiconic两类感受器是感受糖类化合物的味觉感器，推测其可能在红火蚁识别、搜寻及取食扶桑绵粉蚧蜜露过程中发挥重要作用。研究结果明确了蜜露在红火蚁识别、搜寻扶桑绵粉蚧过程中发挥重要作用，揭示了以蜜露为纽带的红火蚁对扶桑绵粉蚧的识别机制，为探明蚂蚁与粉蚧类产蜜昆虫的互作行为机制研究提供依据，为互利共生关系下外来入侵生物的检疫与防控提供思路。.