POSSIBLE FUNCTION FOR A PREVIOUSLY DISCOVERED PHEROMONE ON THE LAST STERNITE OF THE ANT TETRAMORIUM-IMPURUM MAYR (HYMENOPTERA, FORMICIDAE, MYRMICINAE)

Experimental results show that, if laid together with a poison gland extract on artificial trails, the ethological factor previously found on the last visible sternite of Tetramorium impurum incites ants to prefer these trails to poison gland ones, as well as newer trails to older ones. It is demonstrated that the foragers effectively deposit onto the ground some factor acting synergistically with poison gland secretions as a trail pheromone. This factor, which may be the one under study, may incite ants to follow preferentially the newest trails traced on their foraging area.