Honeypot ant

Honeypot ants, also called honey ants, are ants which have specialized workers—repletes, plerergates or rotunds—that consume large amounts of food to the point that their abdomens swell enormously. This phenomenon of extreme inflation of the trunk is called physogastry. Other ants then extract nourishment from them, through the process of trophallaxis. They function as living larders. Honeypot ants belong to any of several genera, including Myrmecocystus and Camponotus. They were first documented in 1881 by Henry C. McCook, and described further in 1908 by William Morton Wheeler.

Behaviour

Many insects, notably honey bees and some wasps, collect and store liquid for use at a later date. However, these insects store their food within their nest or in combs. Honey ants are unique in using their own bodies as living storage, used later by their fellow ants when food is otherwise scarce. Designated worker ants, called "repletes," are the main group that store food for the colony. Repletes are fed by other worker ants until their abdomens become swollen with honey. This extreme growth causes the repletes to become mostly immobile as they act as the "living pantry" for the colony. When the liquid stored inside a honeypot ant is needed, the worker ants stroke the antennae of the honeypot ant, causing the honeypot ant to regurgitate the stored liquid from its crop.

Anatomy

The abdomen of species like Camponotus inflatus consists of hard dorsal sclerites (stiff plates) connected by a softer, more flexible arthrodial membrane. When the abdomen is empty, the arthrodial membrane is folded and the sclerites overlap, but when the abdomen fills the arthrodial membrane becomes fully stretched, leaving the sclerites widely separated.