Path minimization during solitary foraging in Aphaenogaster senilis ants

Path minimization, the process of minimizing travel distance to enhance foraging efficiency, has been widely studied across diverse species, ranging from insects, such as honeybees and ants, to vertebrates, such as birds, bats and rodents. In ants, previous research has focused on trail-laying species, where path selection is driven by pheromone concentration gradients with minimal involvement of cognitive processes. In this study, path minimization and the role of individual cognitive abilities in the thermophilic ant Aphaenogaster senilis , which can forage solitarily without laying chemical trails, were investigated. An experimental set-up comprising a bridge between the nest and the foraging arena with four possible paths (one short, two intermediate and one long) was used, where the longest path was 1.5 times the shortest, to evaluate individual- and group-level foraging decisions over three consecutive trials. Results showed that A. senilis ants consistently avoided the longest path for the outbound and homebound journey and significantly preferred the shortest path when transporting food to the nest. In over half of the trips involving the shortest path, the ants chose this path directly. In about 40% of the cases, the ants deviated to the longer path but then turned back to the shorter one. Transitions from the shorter to the longer path were rare, occurring in less than 4% of the cases. These ants also exhibited enhanced foraging efficiency, which is characterized by faster food discovery and increased transport rate across trials. The findings of this study highlight the capacity of A. senilis to improve foraging efficiency through individual decision-making rather than collective pheromone-based processes. This study provides insights into the cognitive mechanism underlying foraging behaviour in nontrail-laying ant species and lays the groundwork for further research into the adaptive foraging strategies of ants. • Aphaenogaster senilis ants can minimize their path during solitary foraging. • Path minimization stems from individual cognition, not group-level decisions. • Individual ants correct path deviations while transporting food.