Source and Additional Information

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John T. Longino
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Crematogaster torosa has a biology very similar to crinosa and rochai. It occurs primarily in open, seasonally dry areas, highly disturbed areas, and pasture edges, although it can also be found in the canopy of mature wet forest. In Costa Rica it is a common species in urban areas such as the various city parks in the capital, San Jos?.

Nests are large, polydomous, distributed in a wide variety of plant cavities. Dead branches and knots in living trees are most often used. In Guanacaste Province in Costa Rica they often occupy ant acacias, and may invade acacias already occupied by Pseudomyrmex. They often construct small carton baffles that restrict nest entrances and small carton pavilions that shelter Homoptera on surrounding vegetation. In some instances they may inhabit cavities in live stems. I found a large nest in the live stems of a Protium branch (Burseraceae) in Corcovado National Park, and I have found nests in live stems of myrmecophytic Acacia and Triplaris. Nest chambers are sometimes filled with alate queens and males. Based on a sample size of two, colony founding is monogynous. In one case I dissected a small colony in south Texas and found a single physogastric queen in the center. In another case I found a lone foundress queen in a dead branch of a Triplaris tree in Costa Rica.

Foraging is primarily diurnal but occasional nocturnal foragers are seen. Workers are generalized scavengers and they frequently visit extrafloral nectaries. Often columns of workers move between nests.