Collaborative Research: Detection, Perception and Utilization of Floral CO2 by Manduca sexta

合作研究：Manduca SEXTAJohn G.Hildebrand和Robert A.Raguso在花蜜喂养中检测、感知和使用花蜜中的二氧化碳许多昆虫对环境二氧化碳(CO2)非常敏感，众所周知，它对吸血物种吸引寄主很重要，但CO2对以花蜜为食的昆虫的行为意义尚不清楚。初步研究结果表明，鹰蛾Manduca sexta(鳞翅目：狮身蜂科)可能会利用新开放的花朵释放出的高浓度二氧化碳，帮助它在觅食过程中找到未开发的花蜜来源。这项研究的主要目的是通过研究花卉CO2感官检测的生态学、行为学和神经生理学方面的研究，确认和确定花卉CO2在飞蛾觅食行为中的作用，从而实现花的授粉。特别是，该项目旨在发现：(1)花蜜含量与花朵前面的二氧化碳浓度之间的关系，无论是在飞蛾造访之前还是之后；(2)Manduca在觅食过程中是否以及如何利用花卉二氧化碳；(3)关于二氧化碳的感官信息是如何处理的，并与飞蛾大脑中有关花香的信息相结合。在AIM(2)中对觅食行为的调查在单独的实验中解决了飞蛾是否评估有利可图的单个花朵或植物斑块，以及觅食飞蛾是否利用有关花卉二氧化碳的感官信息来增加它们的花蜜摄入量。我们还将测试飞蛾是单独使用花香二氧化碳，还是与花香气味一起使用。为了实现这些目标，我们将使用实验方法的组合。我们将测量个别飞蛾的行为反应，无论是在实验室(用于在隧道和气候控制的飞行场地中对飞蛾的实验)还是在野外(在室外飞行围栏中)，对人造和天然花朵的行为反应，这些花蜜、二氧化碳和花香的数量各不相同。我们将使用感觉神经生理学技术来记录飞蛾大脑嗅觉中心神经细胞的反应，当二氧化碳和花香化合物单独和一起刺激时。这种方法应该对觅食蛾对花刺激的适应反应及其潜在的神经生物学机制有深入的了解。在其更广泛的影响中，这项研究预计将对农业社区有用，因为许多蛾和其他与植物相关的昆虫是有益的传粉者和/或经济上重要的害虫。通过二氧化碳线索操纵昆虫的行为已经被用来控制蚊子等食血昆虫，在这项研究的基础上，可能会开发出类似的方法来帮助在农业背景下控制飞蛾。这项工作还可能有助于评估如果环境中的二氧化碳水平继续增加(如对全球气候变化的预测那样)，对生态相互作用(食物网、互惠关系)的影响。此外，重要的是，该项目的参与者将从其多学科方法中受益，并在一系列方法和技术挑战方面获得经验。计划有两名本科生参与。这两个合作实验室都有支持和培训少数族裔学生的记录，并将继续这样做。南卡罗来纳州实验室的本科生将从全州少数群体参与研究联盟(SCAMP)中挑选出来，并将每年访问图森，会见项目参与者并参加外联活动。研究成果将在科学会议上以书面和口头形式传播，并通过以公众为目标的机构，如亚利桑那州-索诺拉沙漠博物馆。

COLLABORATIVE RESEARCH: DETECTION, PERCEPTION AND USE OF FLORAL CO2 IN NECTAR FEEDING BY MANDUCA SEXTAJohn G. Hildebrand and Robert A. RagusoUniversity of Arizona and University of South CarolinaMany insects are sensitive to environmental carbon dioxide (CO2), and it is known to be important for attraction of blood-feeding species to their hosts, but the behavioral significance of CO2 for insects that feed on floral nectar is largely unclear. Preliminary studies yielded findings suggesting that the hawkmoth Manduca sexta (Lepidoptera: Sphingidae) may use elevated CO2, emitted by newly opened flowers, to help it find unexploited nectar sources during foraging. The principal goal of the proposed research is to confirm and establish the roles of floral CO2 in moths' foraging behavior, and hence pollination of flowers, by investigating ecological, behavioral, and neurophysiological aspects of the sensory detection of CO2 in Manduca. In particular, the project aims to discover: (1) the relationship between a flower's nectar content and CO2 concentration in front of the flower, both before and after a moth's visit; (2) whether and how Manduca uses floral CO2 during foraging; and (3) how sensory information about CO2 is processed and integrated with information about floral scent in the moth's brain. The investigation of foraging behavior in aim (2) addresses, in separate experiments, whether moths evaluate profitable individual flowers or plant patches, and whether foraging moths use sensory information about floral CO2 to increase their nectar intake. We also will test whether moths use floral CO2 alone or in conjunction with floral odor. To achieve these aims, we will use a combination of experimental approaches. We will measure behavioral responses of individual moths, both in the laboratory (for experiments on flying moths in a tunnel and in a climate-controlled flight arena) and in the field (in outdoor flight enclosures), to artificial and natural flowers that vary in the amounts of nectar, CO2, and floral scent that they emit. We will use the techniques of sensory neurophysiology to record responses of nerve cells in the olfactory center of the moth's brain, when the moths are stimulated with CO2 and floral-scent compounds, both separately and together. This approach should yield insights about the adaptive responses of foraging moths to floral stimuli and their underlying neurobiological mechanisms. Among its broader impacts, this research is expected to be useful to the agricultural community, as many moths and other plant-associated insects are beneficial pollinators and/or economically important pests. Manipulation of insect performance via CO2 cues is already used to control blood-feeding insects such as mosquitoes and, on the basis of this research, may be developed similarly to help control moths in an agricultural context. This work may also help to assess the consequences for ecological interactions (food webs, mutualisms) if ambient levels of CO2 continue to increase, as is predicted for global climate change. Importantly, moreover, participants in the project will profit from its multidisciplinary approach and gain experience with a range of methods and technical challenges. Involvement of two undergraduate students is planned. Both collaborating laboratories have records of supporting and training minority students and will continue to do so. The undergraduate student in the South Carolina laboratory will be chosen from the state-wide SC Alliance for Minority Participation in Research (SCAMP) and will visit Tucson each year to meet with project participants and participate in outreach activities. Research findings will be disseminated in written and oral form at scientific conferences and through institutions targeting the public, e.g. the Arizona-Sonora Desert Museum.