A vast diversity of parasites associate with ants. Living in and around ant nests these organisms must overcome ant colony defenses. As ant defensive behavior is mainly mediated by species-specific cuticular hydrocarbons (CHCs) or alarm pheromones, ant-associated parasites can either crack their hosts chemical communication code by modifying their own CHC-profiles or use pro-active strategies like chemical weaponry for distraction and repellency. While the chemical nature of ant-parasite interactions has been intensively studied for highly host specific parasites, the chemical-deceptive strategies of the rather rare ant-resembling Heteropterans are unknown. To gain insight into this system, I studied the bug Scolopostethus pacificus (Barber 1918) which can be found near the nests of the ecologically dominant and aggressive velvety tree ant (Liometopum occidentale, Emery 1895). Using behavioral, chemical and molecular approaches I disentangled the relationship of S. pasificus and its host ant. Chemical profiling of the bug and the ant revealed that the bug does not make use of CHC insignificance or mimicry, but instead uses a cocktail of volatile compounds released from its metathoracic glands that likely moderates encounters with its aggressive host. Feeding trials with armed and artificially disarmed bugs revealed a defensive function of the gland exudates. Targeted molecular gut barcoding showed that S. pasificus does not feed on L. occidentale. These results suggest that chemical weaponry, rather than a chemical code-cracking CHC matching or chemical insignificance, enables S. pasificus to get along with and live in close proximity to its host ant.

中文翻译：

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使用武器代替香水–嗜冰臭虫Scolopostethus pacificus（Rhyparochromidae）的化学缔合策略

蚂蚁与多种寄生虫有关。这些生物生活在蚂蚁巢内或周围，必须克服蚁群的防御。由于蚂蚁的防御行为主要是由特定物种的表皮碳氢化合物（CHC）或警报信息素介导的，因此与蚂蚁相关的寄生虫可以通过修改自己的CHC配置文件来破解宿主的化学通讯代码，也可以使用化学武器等主动策略来分散注意力和排斥性。尽管已经针对高度寄主的特定寄生虫深入研究了蚂蚁与寄生虫相互作用的化学性质，但相对罕见的类似于蚂蚁的类鳞翅目昆虫的化学欺骗策略仍是未知的。为了深入了解该系统，我研究了臭虫Scolopostethus pacificus（Barber 1918），可以在生态上占主导地位且具侵略性的天鹅绒树蚂蚁（Liometopum occidentale，Emery 1895）的巢穴附近找到。使用行为，化学和分子方法，我解开了帕氏链球菌与其宿主蚂蚁的关系。对臭虫和蚂蚁的化学分析表明，该臭虫没有利用CHC的微不足道或模仿，而是使用了从其后胸腺释放的挥发性化合物的混合物，可能会缓和其侵略性宿主的遭遇。用武装和人为解除武装的虫子喂养试验表明，腺体分泌物具有防御功能。有针对性的分子肠条码显示，pasificus不以西方乳杆菌为食。这些结果表明，化学武器，而不是破解化学密码的CHC匹配或化学无关紧要的方法，使pasificus能与宿主蚂蚁相处并生活在其附近。