myrmeco-, myrmec-, myrme-, myrmic-, myrmi- +
(Greek: ant, ants)
The normal queen caste has been completely eliminated. Males are rare (23 percent of the entire adult crop during June and July) and nonfunctional.
Reproduction is almost exclusively parthenogenetic by unfertilized workers, who do not differ in any apparent manner from other workers in the colony.
Apparently, the Pristomyrmex pungens colony is asexual. It has come to resemble a vegetatively reproducing plant in its organization.
The concept of "queen" cannot be applied in this case, and it is difficult to classify the species as truly eusocial (group in which individuals display cooperation in caring for the young; reproductive division of labor, with more or less sterile individuals working on behalf of individuals engaged in reproduction).
The presence of these stinging Pseudomyrma ants protects the acacia trees from leaf-eating enemies.
Before maturity, the large acacia thorns are filled with pith and covered by hard, outer walls. When mature, the ants gnaw an entrance hole into one of each pair of thorns and remove all of the soft pith.
The entrance is made near one of the tips. Within the paired thorns, the ants establish their colony and begin rearing their young, well protected by the hard shell-like walls.
It would seem as if the tree had purposely provided these slender little ants with a safe home and apparently, this is true, since the ants pay their rent by protecting the leaves from leaf-eating insects; especially, leaf-cutting ants which are able to defoliate a tree in one night.
Not only does the acacia provide snug homes for its standing army of Pseudomyrma ants; it also furnishes food for them.
At the base of each leaflet-bearing twig, there is a row of crater-like glands which secrete a honey-like liquid upon which the ants feed.
As a result, the ants have food and lodging, and the acacia, in return, receives protection from enemies like leaf-cutting ants or leaf-eating beetles.
They become alert to the mere smell of a cow or a person, and when their acacia tree is brushed or shaken, they swarm out and immediately attack intruders.
Their stings are very painful, causing a lasting burning and throbbing effect. To brush against an occupied acacia, and thus to acquire a group of vicious, stinging ants on an arm or a leg, is a sensation very much like walking into a large nettle plant.
Some of these miniature fungus-growers cut leaves, like their larger relatives the Atta ants, but most of them collect caterpillar droppings, fallen flower petals, and other vegetable materials.
Since Trachymyrmex colonies are never large, only a few ants will be found working in a fungus garden.