A comparative study of navigation behaviours in ants
Ants inhabit a vast range of ecosystems and exhibit wide morphology. They are expert navigators employing a handful of well-understood navigational strategies. However, the specific relationships among ant navigation behaviours, ecology, and morphology remain unclear, highlighting the need for comparative studies across diverse species. Here, we conducted field displacement experiments with 15 ant species across different habitats, assessing the prevalence of path integration, view-based navigation, olfactory trail following, and backtracking. We further tested whether use of particular navigation strategies was correlated with variation in morphological traits that could affect navigation efficiency, namely body size, eye size (view-based, path integration) and scape length (olfactory). There was a negative correlation between path integration and olfaction across different ant species, and no other clear trade-offs were identified between navigational strategies. Olfactory navigation emerged as the most dominant strategy. Path integration was also prevalent but limited to arboreal ants. View-based navigation was observed in both ground-foraging and tree-climbing ant species, and, unexpectedly, backtracking was also widespread. Species with larger eyes and body size showed a stronger preference for view-based navigation. However, no significant relationship was found between eye size or antennal scape length with preference for either path integration or olfaction. These results highlight the diversity and specialization of navigational strategies in ants, which appear to depend on the species ecological niche and morphological traits. Our study confirmed that path integration performs better in open sky environments, while view-based navigation appears more effective in cluttered habitats. We also showed the importance of plasticity in both foraging strategies and navigational profile at individual and colony levels, demonstrating the adaptability of ants navigation strategies to their environment.