Elongate/Mexican Twig Ants


Pseudomyrmex gracilis


The adult ant is best described as a large, 8 to 10-mm, slender ant that, when viewed from above, looks like a wasp without any wings. While its coloration differs greatly, generally this ant ranges from a mixture of dark brown-black to a mixture of orange-brown. It commonly has a dark-colored head and abdomen and a light-orange thorax. Pseudomyrmex gracilis possesses a painful sting, but is not as aggressive as red imported fire ants.


The ants seek hollowed-out cavities of plant material like dead twigs and small branches in order to house their small, single-queen nests. Some of the more typical habitats include rainforests, mangroves, fields that have reverted to secondary growth plants and hardwood trees. Nests have only one, small entrance and may be inhabited by only a few ants. Elongate twig ants excavate nesting cavities themselves if the nesting material is flexible and soft and will also nest in tunnels made wood boring beetles.

Elongate twig ants do not create pheromones to aid in nest relocation. Instead, when they need to move and create another nest, adult workers carry other mature workers, queens and males to the new nest site.

There is little or no ornamental plant or structural damage caused by elongate twig ants, even though these ants have rarely been found nesting in wooden doors inside homes.

Pseudomyrmex gracilis swarms and stings enemy nest invaders. This behavior is important since the elongate twig ant is considered a beneficial insect as a result of preying on pest insects and defending its nest. Unlike many other kinds of ants, elongate twig ants are solitary hunters.


Reproduction begins when the virgin queen leaves the nest to mate with a male reproductive. After mating, the queen begins a new nest by laying eggs and tending the brood. Once the first group of workers develops, the workers take control of colony maintenance and provide food sources, so the queen is only responsible for laying eggs.


Appearance of stinging ants and swarms of winged reproductives are signs of an infestation.


Originally brought to the United States from Mexico, P. gracilis is established in Texas, Florida, Louisiana and Hawaii.


Elongate twig ants are seldom found inside homes and are not numerous outdoors. Therefore, unless they are nesting close to areas frequented by people or pets where a stinging problem could occur, control is usually unnecessary. However, should control become necessary, contact your pest management professional and request an inspection and management plan for ridding your property of elongate twig ants.