Some New Information on Ants’ Cemeteries Organization

Abstract

Aim: We aimed to explain how ants manage to deposit nestmate corpses outside their nest. Methodology: We first summarized a previous study of ours dealing with the subject, and reported others carried out in the meantime by other researchers. Then, we executed a new experimental work on the ant Myrmica ruginodis. We studied the ethological effects of chemical material present at cemetery sites and examined the tracks made by ants going to and from cemeteries. This gave the explanation of how and why ants transport and deposit corpses far from their nests, collectively or individually, and form piles or not. Results: An ant loading a corpse moves away from its nest, discontinuously depositing some of the contents of its Dufour gland. It drops the corpse far from the nest, moves slowly, even rests for a time, and lays down some of its poison gland. Such deposits induce klinokinesis in nestmates and consequently incite nestmates carrying a corpse to approach this place moving slowly, sinuously, and finally to drop their load there, which leads to the formation of piles. When the ant has dropped the corpse, it returns to its nest while depositing, over a short distance, the trail of pheromone issued from its poison gland. Any ants can act similarly and individually. Corpses can thus be piled or laid down anywhere far from the nest. Conclusion: The results of our experiment agree with other researchers’ studies, and explain the apparition of piles of corpses, as well as the presence of corpses at places far from the nest.