Dolichoderus mariae is not a particularly common ant, but once noticed, it is conspicuous by virtue of its uncommon nesting habits and dense populations. It is a polygyne polydomous reddish-brown ant that is abundant in the eastern and central United States. Across the antís range, the ant forms subterranean nests at the base of plants with fibrous roots. This nesting behavior has also been documented in D. mariaeís congeners D. plagiatus (Cole, 1940), D. pustulatus (Wesson and Wesson, 1940), and D. taschenbergi (Trager, pers. comm.). In North Florida D. mariae excavates soil at the base of wiregrass clumps to form its nest (W. Tschinkel, pers. comm.). I explored the natural history of D. mariae through an examination of the antís nest architecture, queen fecundity, polygyny, sociometry, worker-size variation, division of labor, colony demography, spatial distribution of nests, feeding biology, and seasonal variation in these characteristics. The antís nest architecture consists of a shallow, single, large conical chamber. The nests lack common nest elements such as tunnels and chambers. Sociometry revealed that the ant is monomorphic, and the colony cycle is dominated by strong seasonal polydomy. The area occupied by a colony is similar year to year even though the colony contracts down to one or two nests. Within their territory range, the ants are following and exploiting their food source of honeydew that is provided by different homopterans. Possibly polydomy is an adaptation to exploit the dispersed and rapid changing populations of homopterans, which in turn allows polygyny and extreme colony growth rates. Because D. mariae has above ground trails, a dependence on homopterans on low plants (e.g. bracken ferns and runner oak), and shallow nests, it seems likely that fire effects D. mariae colonies. However, more research is needed to determine the nature and extent of the effects of fire. Finally, the ant may have considerable ecological importance to the long-leaf pine ecosystem. Since colony size may exceed several million workers who carpet the landscape, they probably play a substantial role in energy flow. In addition, since the abandoned nests retain their conical shape, they provide shelter for a variety of invertebrates (e.g. spiders) and small vertebrates (e.g. snakes, rodents, and lizards).