Pogonomyrmex rugosus
Pogonomyrmex rugosus, the Rough Harvester Ant, is fairly common throughout Arizona's deserts. They usually prefer somewhat drier deserts than their close relative Pogonmyrmex barbatus. Pogonomyrmex rugosus is usually brownish-black in color, but this can be quite variable. It is tempting to use coloration to differentiate P. rugosus from P. barbatus, since P. barbatus is usually red. You can't always rely on this characteristic, though, since some populations of P. rugosus are red in coloration.

Pogonomyrmex rugosus nest entrances are usually surrounded by a patch of bare ground. Sometimes there will be coarse gravel gathered by the ants around the entrance. When P. rugosus forages, they will often use the same trails repeatedly, until they have worn an "ant superhighway" through the vegetation.


  

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Pogonomyrmex rugosus worker picking up a large pebble. She is going to use this pebble to seal her nest entrance. Many ants seal their nest entrances before entering periods of inactivity, presumably to better keep out predators and parasites.
Pogonomyrmex rugosus worker picking up a large pebble. She is going to use this pebble to seal her nest entrance. Many ants seal their nest entrances before entering periods of inactivity, presumably to better keep out predators and parasites.
Pogonomyrmex rugosus worker sealing her nest entrance with pebbles. A few of the workers usually get sealed outside of the nest, as this one is likely to.
Pogonomyrmex rugosus worker sealing her nest entrance with pebbles. A few of the workers usually get sealed outside of the nest, as this one is likely to.
Pogonomyrmex worker. The long, curved hairs underneath her head are called a 'psammaphore'. Scientists think that the psammaphore helps the ants to carry loose soil, such as sand.
Pogonomyrmex worker. The long, curved hairs underneath her head are called a 'psammaphore'. Scientists think that the psammaphore helps the ants to carry loose soil, such as sand.
Pogonomyrmex rugosus nests usually have a large, circular area around them that is devoid of vegetation. This photo shows what happened to the vegetation. This plant is in the process of having all of its leaves chewed off by a recently established Pogonomyrmex nest. The ants will chew the leaves off, and as many of the stems as they can, until the plant dies.
Pogonomyrmex rugosus nests usually have a large, circular area around them that is devoid of vegetation. This photo shows what happened to the vegetation. This plant is in the process of having all of its leaves chewed off by a recently established Pogonomyrmex nest. The ants will chew the leaves off, and as many of the stems as they can, until the plant dies.
A red Pogonomyrmex rugosus worker carries dirt away from her nest.
A red Pogonomyrmex rugosus worker carries dirt away from her nest.
In spite of their fierceness towards larger animals, Pogonomyrmex workers are often not especially pugnacious towards other ants. Here a Dorymyrmex bicolor ant crawls over a Pogonomyrmex rugous worker. The Pogonomyrmex stood very still, with her legs extended and her head pushed down to the ground, while the Dorymyrmex crawled over her.
In spite of their fierceness towards larger animals, Pogonomyrmex workers are often not especially pugnacious towards other ants. Here a Dorymyrmex bicolor ant crawls over a Pogonomyrmex rugous worker. The Pogonomyrmex stood very still, with her legs extended and her head pushed down to the ground, while the Dorymyrmex crawled over her.
Territorial conflicts between Pogonomyrmex rugosus nests are pretty common. The desert floor will be littered with dismembered ants after some of these battles.
Territorial conflicts between Pogonomyrmex rugosus nests are pretty common. The desert floor will be littered with dismembered ants after some of these battles.
Typical Pogonomyrmex rugosus nest entrance, with workers emerging. My finger is in the upper left of the photo, for scale.
Typical Pogonomyrmex rugosus nest entrance, with workers emerging. My finger is in the upper left of the photo, for scale.
Pogonomyrmex rugosus worker carries a seed back to her nest.
Pogonomyrmex rugosus worker carries a seed back to her nest.