Thetropical carpenter ants ( Camponotus Leonardi )they live high in the treetops.When they are infected by a parasitic fungus ( Ophiocordyceps unilateralis ) the behavior of these ants changes drastically, behave erratically and act likezombies. The fungus manipulates them to death to obtain optimal conditions for reproduction. The new research, published in the journalBMC Ecology, examines the patterns of altered behavior in these ants and shows how the fungus alters the behavior of ants.
The authors studied carpenter ants infected with the fungus in the jungle of Thailand.O. unilateralis. As it develops, the fungus spreads through the ant’s body and head causing the muscles to atrophy. The fungus also affects the ant’s central nervous system and while normal ants rarely leave the tracks they work for by hauling food to the anthill,zombies walk in a random way, unable to find their way home. Ants also sufferseizures that cause them to fall from trees. Once on land they were unable to find their way back to the canopy and stayed in an understory area that was cooler so that the fungus could develop.
At solar noon (when the sun is at its strongest)the fungus synchronized the behavior of the infected ants, forcing them to bite the main vein on the underside of a leaf. The multiplication of fungal cells in the heads of ants causes the fibers within the muscles that open and close their jaws to shed. This results in a “latch hook,” which means that an infected ant is unable to release the blade after death. A few days later, the fungus generates a fruiting body (stroma) on the ant’s head that releases spores to be picked up by another wandering ant.
Dr. David Hughes of Penn State University has explained that the fungus attacks ants on two fronts. “Firstly by using the ant as a food source, and secondly throughtheir muscles and central nervous system, giving rise to zombies that end up in the humid undergrowth“This behavior of infected ants is essentially a widespread fungal phenotype (the behavior of fungi throughout the ant’s body).
