Stigmatomma pallipes

Identification
The genus Amblyopone with 74 species world wide occurs in tropical and subtropical leaf litter, preying on arthropods. There are three species of Amblyopone in North America.

Amblyopone trigonignatha Brown 1949. This species is known only from a single specimen that was extracted from leaf litter with a Berlese funnel. It was found in Concord County, North Carolina.

A. oregonensis is found in British Colombia, Washington, Oregon, northern California and extends eastward into mesic areas of the Pacific Northwest.

Ambylopone pallipes found in the Eastern United States is not a common ant, but it can be discovered by turning over stones and searching carefully through rotten wood on the ground. These small, dark reddish-brown ants are about ¼ inch in length. The eyes are very small, with only one or two facets. There is a row of small teeth on the anterior margin of the clypeus and the mandibles are long and linear with a row of bi-dentate teeth on the inner margin. The petiole is broadly joined to the gaster.

Distribution
This species is widely distributed in the United States. It has been reported from most eastern states except Maine and Pennsylvania. It is also known from California and is found sporadically in the mountains of Arizona.

This taxon was described from the United States.

Habitat
The small colonies are most common in wooded areas where they are found in rotten logs and under stones. They prefer moist, cool habitats. Centipedes and beetle larvae appear to be the main food source. In New England these ants are often found nesting under rock walls.

Abundance
This ant species is seldom if ever abundant. Due to their small colony size and nest location under rocks and in logs in forests, this ant species is difficult to find.

Biology
Colony size is small, often less than 20 to 50 workers. The workers are slow moving, and forage under ground and in rotten logs where they are difficult to find. The pupae are covered with a brown silk case that helps in identification in the field. The queen is worker-like and inconspicuous. The males and females mate during the late summer months. Females mate with males on rocks on the ground in forested areas during the first week of September in New England.

Foraging/Diet
The highly modified mandibles appear to be specialized for hunting centipedes. Predators of centipedes and beetle larvae in forest litter.

Colony Attributes
The colony size is relatively small; often less than 50 workers.

Nesting Biology
Nest under stones and in old logs.

Reproduction
Single reproductive queen.

Behavior
Primitive social structure with no trophallaxis.

Associations with other Organisms
It is possible that Pyramica species are most often found under the same stone.

Common Name
Pale Footed Primitive Ant

Etymology
Pale-footed

Additional References

 * [[Media:Creighton 1940b.pdf|Creighton, W. S. 1940b. A revision of the forms of Stigmatomma pallipes. Am. Mus. Novit. 1079: 1-8 PDF]]


 * [[Media:Traniello 1982.pdf|Traniello, J.F.A. 1982. Population structure and social organization in the primitive ant Amblyopone pallipes. Psyche 89: 65-80. [17.xii.1982.] PDF]]


 * Ward, P. S. 1988. Mesic elements in the western Nearctic ant fauna: taxonomic and biological notes on Amblyopone, Proceratium and Smithistruma (Hymenoptera: Formicidae). J. Kans. Entomol. Soc. 61: 102-124.