Merienne Hugo, Latil Gérard, Moretto Pierre, Fourcassié Vincent
Centre de Recherches sur la Cognition Animale, Centre de Biologie Intégrative, Université de Toulouse, CNRS, UPS, Toulouse, France.
PeerJ. 2021 Jan 29;9:e10664. doi: 10.7717/peerj.10664. eCollection 2021.
Ants are well-known for their amazing load carriage performances. Yet, the biomechanics of locomotion during load transport in these insects has so far been poorly investigated. Here, we present a study of the biomechanics of unloaded and loaded locomotion in the polymorphic seed-harvesting ant (Linnaeus, 1767). This species is characterized by a strong intra-colonial size polymorphism with allometric relationships between the different body parts of the workers. In particular, big ants have much larger heads relative to their size than small ants. Their center of mass is thus shifted forward and even more so when they are carrying a load in their mandibles. We investigated the dynamics of the ant center of mass during unloaded and loaded locomotion. We found that during both unloaded and loaded locomotion, the kinetic energy and gravitational potential energy of the ant center of mass are in phase, which is in agreement with what has been described by other authors as a grounded-running gait. During unloaded locomotion, small and big ants do not display the same posture. However, they expend the same amount of mechanical energy to raise and accelerate their center of mass per unit of distance and per unit of body mass. While carrying a load, compared to the unloaded situation, ants seem to modify their locomotion gradually with increasing load mass. Therefore, loaded and unloaded locomotion do not involve discrete types of gait. Moreover, small ants carrying small loads expend less mechanical energy per unit of distance and per unit of body mass and their locomotion thus seem more mechanically efficient.
蚂蚁以其惊人的负载搬运能力而闻名。然而，迄今为止，对这些昆虫在负载运输过程中的运动生物力学研究甚少。在此，我们展示了一项关于多态性收获种子蚁（林奈，1767年）空载和负载运动生物力学的研究。该物种的特点是蚁群内部存在强烈的体型多态性，工蚁身体不同部位之间存在异速生长关系。特别是，大型蚂蚁相对于其体型而言，头部比小型蚂蚁大得多。因此，它们的质心向前移动，当它们用下颚搬运负载时，这种情况更加明显。我们研究了蚂蚁在空载和负载运动过程中质心的动态变化。我们发现，在空载和负载运动过程中，蚂蚁质心的动能和重力势能是同相的，这与其他作者所描述的接地跑步步态一致。在空载运动过程中，小型和大型蚂蚁的姿势不同。然而，它们每单位距离和每单位体重提升和加速质心所消耗的机械能是相同的。在搬运负载时，与空载情况相比，蚂蚁似乎会随着负载质量的增加逐渐改变其运动方式。因此，负载和空载运动并不涉及离散的步态类型。此外，搬运小负载的小型蚂蚁每单位距离和每单位体重消耗的机械能更少，因此它们的运动似乎在机械效率上更高。
