Illumination of behavior leading to host exploitation by a context-dependent mutualist

寄生的生活方式比所有其他生活方式的总和更常见，宿主-寄生虫的相互作用塑造了食物网，影响了行为，并改变了种群的规模和结构。由于昆虫分布广泛，种类繁多，数量众多，而且大多数是寄生的，因此它们是物种相互作用研究的理想对象。这项提议的研究利用了一种独特的寄生虫系统——很容易在实地研究和实验室操作——来解决物种相互作用的关键问题。研究目标是确定导致专性共生（不同物种共同生活）的行为，同时考虑到相互作用实体（蚂蚁，真菌和细菌）的网络。这项综合研究在其范围上是原创的，跨越了时间和生物尺度，但在使用综合方法（群体遗传学，形态学，化学生态学，行为）以更好地理解共生关系方面也具有创造性。具有魅力的Megalomyrmex客蚁/养真菌蚂蚁宿主/寄生虫系统有可能重塑共生关系的感知方式，同时提供一个新的模型，以满足现在和未来学生和研究人员的需求。此外，这些努力将让学生参与研究，并创建一个基于双语在线徽章的暑期教育项目，由不同的榜样领导，以保护共生生物为中心，提高STEM教育的可及性。这项研究将使寄生虫学和社会生物学领域之间的交流成为可能。对称巨蚁（Megalomyrmex symmetochus）是一种专性的“客蚁”寄生虫，寄生于一种种植真菌的蚂蚁——amabilis绢蟹（Sericomyrmex amabilis）。当更致命的寄生虫威胁宿主时，寄主蚂蚁的成本可以迅速转化为净收益，因为寄主蚂蚁通过其生物碱毒液武器提供保护。动物行为的综合方法，遵循寄生虫学开发框架，将阐明这些依赖于环境的互惠主义者如何影响共生网络。目标按导致开发的各个阶段进行组织，从启动强制性共生相互作用（寻找宿主/分散）（目标一）到群体整合和物种网络维持（目标二和目标三）。目的1比较宿主及其寄生虫的传播能力和种群动态，利用飞行形态学和种群基因组学方法。寄主寻找策略将首次确定在一个社会寄生虫（一个社会有机体寄生另一个）使用简化的方法。不仅蚂蚁和真菌花园挥发物的特征，而且吸引寄主和寄生蚂蚁的化合物将被发现。目的II和III主要研究寄生虫毒液的功能。毒性和行为分析将测试当暴露于寄生虫衍生的毒液生物碱时，被寄生和未被寄生的蚁群在生理和行为上是否存在差异。16S宏基因组学、基于培养的分析和操作实验将区分细菌共生体，并确定哪些对抗菌生物碱毒液敏感。这项工作通过确定社会寄生虫如何解决所有寄生虫面临的挑战以实现成功利用，填补了一个重大空白。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Parasitic lifestyles are more common than all other lifestyles combined and host-parasite interactions shape food webs, influence behavior, and alter population size and structure. Because insects are widespread, hyper-diverse, and abundant, and most are parasitic, they are ideal subjects for species interaction studies. The proposed study leverages a unique parasite system—easily studied in the field and manipulated in the lab—to address key questions about species interactions. The research objective is to identify behaviors that lead to obligate symbioses (different species living together), while taking into consideration a network of interacting entities (ants, fungus, and bacteria). This comprehensive study is original in its scope, spanning temporal and biological scales, but is also creative in the use of integrative methods (population genetics, morphology, chemical ecology, behavior) to better understand symbiotic relationships. The charismatic Megalomyrmex guest ant/fungus-farming ant host/parasite system has the potential to reshape the way symbioses are perceived while providing a new model that will serve the needs of students and researchers now and in the future. Additionally, these efforts will include students in research and create a bilingual online badge-based educational summer program, led by diverse role models, and centered on conservation of symbioses, enhancing accessibility to STEM education.This study will enable much-needed crosstalk among the fields of parasitology and sociobiology. Megalomyrmex symmetochus is an obligate ‘guest ant’ parasite of a fungus-farming ant, Sericomyrmex amabilis. The costs of hosting guest ants can quickly shift to a net benefit when a more lethal parasite threatens hosts, because the guest ants offer protection through their alkaloidal venom weaponry. Integrative approaches in animal behavior, following a parasitological exploitation framework, will clarify how these context-dependent mutualists influence symbiotic networks. Aims are organized by the stages leading to exploitation, from the initiation of an obligate symbiotic interaction (host-finding/dispersal) (Aim I) to colony integration and species network maintenance (Aims II and III). Aim I compares dispersal ability and population dynamics of hosts and their parasites, capitalizing on flight morphology and population genomics methods. Host-finding strategies will be identified for the first time in a social parasite (one social organism parasitizing another) using a reductionist approach. Not only will ant and fungus garden volatiles be characterized but compounds that attract the host and parasite ants will be discovered. Aims II and III center on parasite venom function. Toxicity and behavioral assays will test if parasitized and non-parasitized ant colonies differ physiologically and behaviorally when exposed to parasite-derived venom alkaloids. 16S metagenomics, culture-based assays, and manipulation experiments will distinguish bacterial symbionts and determine which are susceptible to antimicrobial alkaloidal venom. This work fills a significant gap by identifying how social parasites solve the challenges all parasites face to achieve successful exploitation.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.