Ants show remarkable ecological and evolutionary success due to their social life history and division of labour among colony members. In some lineages, the worker force became subdivided into morphologically distinct individuals (i.e. minor versus major workers), allowing for the differential performance of particular roles in the colony. However, the functional and ecological significance of these morphological differences are not well understood. Here, we applied finite element analysis (FEA) to explore the biomechanical differences between major and minor ant worker mandibles. Analyses were carried out on mandibles of two Pheidole species, a dimorphic ant genus. We tested whether major mandibles evolved to minimize stress when compared to minors using combinations of the apical tooth and masticatory margin bites under strike and pressure conditions. Majors performed better in pressure conditions yet, contrary to our expectations, minors performed better in strike bite scenarios. Moreover, we demonstrated that even small morphological differences in ant mandibles might lead to substantial differences in biomechanical responses to bite loading. These results also underscore the potential of FEA to uncover biomechanical consequences of morphological differences within and between ant workers.

由于蚂蚁的社会生活史和群体成员之间的劳动分工，蚂蚁在生态和进化方面表现出了显着的成功。在一些谱系中，工蚁被细分为形态上不同的个体（即次要工蚁与主要工蚁），从而允许在群体中不同的特定角色表现。然而，这些形态差异的功能和生态意义尚不清楚。在这里，我们应用有限元分析（FEA）来探索主要和次要工蚁下颌骨之间的生物力学差异。对两种Pheidole物种（一种二态性蚂蚁属）的下颌骨进行了分析。我们测试了在撞击和压力条件下，使用根尖齿和咀嚼边缘咬合的组合，与小下颌相比，大下颌是否进化到最小化压力。专业人士在压力条件下表现更好，但与我们的预期相反，未成年人在罢工情况下表现更好。此外，我们证明，即使蚂蚁下颌骨的微小形态差异也可能导致对咬合载荷的生物力学反应存在显着差异。这些结果还强调了有限元分析在揭示工蚁内部和工蚁之间形态差异的生物力学后果方面的潜力。