Comparison of foraging tool use in two species of myrmicine ants (Hymenoptera: Formicidae)

The tool-using behavior of Aphaenogaster species has been well studied in the past few years, however, our knowledge of other myrmicine ants is rather limited. The aim of the present study was to compare the tool-using behavior of two closely related myrmicine ants with different feeding behaviors: Aphaenogaster subterranea, an omnivorous species, and Messor structor, a mainly granivorous species, which is also known to use tools when feeding on liquids. We tested the hypothesis that due to the difference in diet, the tool-using behavior differs in these two species being more complex and dynamic in A. subterranea than in M. structor. Consistent with our hypothesis, the foraging workers of M. structor dropped and retrieved significantly less tools into/from honey-water baits than A. subterranea, and, contrary to the latter species, showed no preference towards any specific tools. In addition, tool dropping was significantly slower in M. structor, and the dropping and retrieving of tools...