Evolution of thorax architecture in ant castes highlights trade-off between flight and ground behaviors

The concerted evolution of morphological and behavioral specializations has compelling examples in ant castes. Unique to ants is a marked divergence between winged queens and wingless workers, but morphological specializations for behaviors on the ground have been overlooked. We analyzed thorax morphology of queens and workers in species from 21 of the 25 ant subfamilies. We uncovered unique skeletomuscular modifications in workers that presumably increase power and flexibility of head–thorax articulation, emphasizing that workers are not simply wingless versions of queens. We also identified two distinct types of queens and showed repeated evolutionary associations with strategies of colony foundation. Solitary founding queens that hunt have a more worker-like thorax. Our results reveal that ants invest in the relative size of thorax segments according to their tasks. Versatility of head movements allows for better manipulation of food and objects, which arguably contributed to the ant...

形态特化与行为特化的协同演化在蚁类品级中拥有诸多极具说服力的实例。蚁类所独有的显著分化体现为具翅蚁后与无翅工蚁之间的差异，但针对地面行为的形态特化却长期被学界忽视。我们分析了覆盖25个蚁亚科中21个亚科的物种类群的蚁后与工蚁胸部形态。我们发现工蚁存在独特的骨骼肌肉特化，推测该特化可提升头胸关节的运动力量与灵活性，这也证实工蚁并非仅仅是无翅的蚁后变体。我们还鉴定出两种截然不同的蚁后类型，并发现它们与不同的蚁群奠基策略存在反复出现的演化关联。以独自觅食方式进行蚁群奠基的蚁后，其胸部结构更接近工蚁。我们的研究结果表明，蚁类会根据不同职能调整胸部各节的相对尺寸。头部运动的多功能性使其能够更出色地操控食物与各类物体，这被认为是推动蚁类