Pseudomyrmex ferruginea

Pseudomyrmex ferruginea
Pseudomyrmex ferrugineus worker
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Hymenoptera
Family:	Formicidae
Subfamily:	Pseudomyrmecinae
Genus:	Pseudomyrmex
Species:	P. ferruguinea
Binomial name
Pseudomyrmex ferruginea F. Smith, 1877

The acacia ant (Pseudomyrmex ferruginea) is a species of ant of the genus Pseudomyrmex. These arboreal, wasp-like ants have an orange-brown body around 3 mm in length and very large eyes. The acacia ant is best known and named for living in symbiosis with the bullhorn acacia (Acacia cornigera) throughout Central America.

The ant and the acacia exemplify a coevolution of a mutualistic system, as described by evolutionary ecologist Daniel Janzen.

P. ferruginea is an obligate plant ant that occupies at least five species of acacia (A. chiapensis, A. collinsii, A. cornigera, A. hindsii and A. sphaerocephala). Its life cycle conforms to the claustral pattern of ants in general.

To repel herbivorous animals, various acacias protect their succulent leaves with one of several methods, including vicious-looking spines, repellent, noxious chemicals, and —as in the case of the bull's horn acacia— by developing a mutualism with the Acacia ant.

The symbiotic relationship begins when a newly mated queen gets attracted by the odour from the tree and starts nesting inside the large hollow acacia thorns. The queen nibbles into the thorn to lay 15-20 eggs to produce the first generation of workers. As the colony grows, more of the bulbous thorns get inhabited, and when the colony reaches some 400 individuals the ants start to act as gardeners.

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Wikipedia