Allomerus decemarticulatus is an Amazonian ant species found in the tropics of South America. This species is most notable for the workers' complex and extreme predatory behavior, which involves a symbiosis with both a plant and fungal species.

They live in leaf pockets of a host plant species, Hirtella physophora. These leaf pockets are areas inside of the plant between the leaves and the stem. Each colony, which consists of about 1,200 workers, inhabits a single tree; however, the ants are spread among the leaf pockets, with typically 40 workers per pocket. Their diet primarily consists of large insects that are captured on the plant, but they also eat some kinds of food bodies produced by the plant as well as its nectar. They are able to capture their prey, which is much larger than themselves, by constructing a platform that acts as a trap for the unsuspecting prey. The ants hide in the trap and attack when any insect lands on it. This technique is an example of ambush predation. They live and hunt on H. physophora, living in leaf pouches and patrolling the plant's stem for prey.

Plant mutualism

The relationship between A. decemarticulatus and H. physophora is very specialized. H. physophora is a small tree in the Amazonian rainforest that resides in the undergrowth.

Another noteworthy observation is that, unlike typical mutualisms between ants and fungus, these ants do not receive any nutrition from the fungus. They strictly manipulate the physiology of the fungus to construct a mortar for a trap that is able to catch much larger prey.

Similar to the ants, Z. annulosus normally lives on younger H. physophora individuals, where the females lay eggs on the stem. As they begin to develop, the young bugs will live among the trichomes of the stem and hunt on the leaves of the plant. The relationship between the assassin bug and the plant acts independently from that between the ants and the plant. One difference between the two relationships, however, is that the assassin bugs do not take any food source from the plant like the ants do. cultivating a fungus (like in leafcutter ants), and sneaking up to and ambushing larger prey (like in Azteca andreae, another species studied by Dejean). However, most remarkably, Allomerus decemarticulatus seems to incorporate each of these advanced behaviors to make a powerful apparatus for tricking impressively large prey.

References

  • Youtube video
  • "The Myrmicine ant genus Allomerus Mayr (Hymenoptera:Formicidae)" Article
  • "Torture Racks" Are First Known Traps Made by Ants - National Geographic article