Survival of workers and queens of the ant Temnothorax nylanderi depending on infection with the cestode Anomotaenia brevis

Parasites can mediate severe fitness costs and are thus important selective forces shaping the evolution of host phenotypes. Social insects are hosts for a diverse group of parasites, but their impact on the phenotypic traits of their social hosts is still poorly understood. Here, we tracked the survival of tapeworm-infected ant workers, their uninfected nestmates and of ants from unparasitized colonies. Our three-year study on the ant Temnothorax nylanderi, the intermediate host of the cestode Anomotaenia brevis, revealed a prolonged lifespan of infected workers compared to their healthy peers. Indeed, their survival rates resembled those of queens, whose lifespan can reach two decades. In contrast, uninfected workers suffered from increased mortality compared to workers from unparasitized colonies. Infected workers exhibit a metabolic rate and lipid content similar to young workers and they receive more social care than uninfected workers and queens. This increased attention could be ...

寄生虫（parasites）可介导严重的适合度成本（fitness costs），因此是塑造宿主表型（host phenotypes）演化的关键选择压力（selective forces）。社会性昆虫（social insects）是多种寄生虫的宿主类群，但其对社会性宿主表型性状（phenotypic traits）的影响仍未得到充分解析。本研究针对绦虫Anomotaenia brevis的中间宿主（intermediate host）尼氏扁胸切叶蚁（Temnothorax nylanderi）开展了为期三年的追踪实验，我们监测了感染绦虫的工蚁（ant workers）、其未受感染的巢友（uninfected nestmates）以及来自未寄生蚁群（unparasitized colonies）的蚂蚁的存活情况。研究结果显示，相较于健康同龄工蚁，受感染工蚁的寿命显著延长。事实上，受感染工蚁的存活率可与寿命可达二十年的蚁后（queens）相媲美。与之形成鲜明对比的是，未受感染的巢友死亡率显著高于未寄生蚁群中的工蚁。受感染的工蚁其代谢速率（metabolic rate）与脂质含量（lipid content）均与年轻工蚁相近，且相较于未受感染的工蚁与蚁后，它们能获得更多的社会抚育（social care）。这种额外的社会关注可能……