Costa Rica, Panama, Ecuador. Costa Rica: widespread.
Most observations of A. flavigaster have been made in the southern Pacific lowlands of Costa Rica, in moderately seasonal evergreen forest. Azteca flavigaster is a generalist cavity nester with conspicuous surface-foraging workers. In a degraded patch of forest near Quepos, at a pasture edge, I observed abundant workers on the trunk of a live, 40cm diameter tree, emerging from a long narrow fissure at the base. Abundant workers were also on the base of another small tree in the same forest patch. This tree had a dead branch at ground level with workers, brood, and scattered alate females in two parallel cavities, each with horizontal carton partitions. Large columns of workers went up the trunk to a larger dead branch further up. In a patch of mature forest near Ciudad Neily an aggregation of workers were in cavities in the main stem of a sapling of Grias (Lecythidaceae). At Sirena in Corcovado National Park I made several observations of this species. I observed a column of foraging workers on the ground surface, flowing in and out of a 4cm diameter hole extending horizontally into the ground. I observed workers 18m high in the canopy of a Perebea trophophylla (Moraceae) tree, with an aggregation of workers in a small knot. I observed an incipient colony in an Acacia alleni tree, the common myrmecophytic acacia in Corcovado. The tree was in poor shape, without a dominant Pseudomymex colony. The Azteca occupied several of the thorns, one of which contained a physogastric queen and small brood. Finally, I observed two founding queens in a dead and tattered Costus (Costaceae) inflorescence. The inflorescence was filled with many old chambers containing dead Azteca queen remains. The two living queens were in adjacent chambers, but not in contact. Each had brood, and one had nanitic workers. When I put the queens together in the same vial, they immediately locked mandibles in combat. Other researchers at Sirena have collected founding queens in chambers of Tetrathylacium costaricensis and T. macrophyllum.
Workers with the same coloration and habitus of Azteca flavigaster occur in the Atlantic lowlands of Costa Rica, but are rare. At La Selva Biological Station these workers have been collected twice. A worker was collected in a Berlese sample of canopy soil and epiphytes, and a nest or nest fragment was found in a live branch of Coussapoa (Cecropiaceae). The nest also contained workers of Camponotus atriceps, in a parabiotic association.
Although workers matching A. flavigaster have been found on the Atlantic side of Costa Rica and in other countries, no queens have been collected to confirm these identifications. However, the new species A. quadraticeps is known only from queens from the Atlantic lowlands. It is possible that A. quadraticeps and A. flavigaster are allopatric or parapatric sister taxa with similar workers, and that the Atlantic slope workers with yellow gasters are actually the workers of A. quadraticeps.
Found most commonly in these habitats: 1 times found in degraded wet forest edge, 4 times found in rainforest, 4 times found in lowland rainforest, 1 times found in tropical moist forest, 1 times found in lowland wet forest, 1 times found in tropical dry forest, 1 times found in wet forest canopy, 1 times found in CCL 400 m, 1 times found in Edge of second growth rainforest, 1 times found in montane wet forest, ...
Collected most commonly using these methods or in the following microhabitats: 11 times search, 2 times Malaise, 1 times Berlese, 1 times Fogging, 1 times light trap
Elevations: collected from 20 - 350 meters, 82 meters average