Paratrechina steinheili (Forel 1893)

Formicinae, Formicidae, Hymenoptera, Insecta, Arthropoda, Animalia

worker face view

worker lateral view


Throughout the Neotropics, from southern Mexico to southern Brazil, many Caribbean islands. Costa Rica: throughout the country in all lowland to mid-elevation habitats.


Scape with macrochaetae conspicuous, long, strongly differentiated from appressed pubescence; color generally brown with contrastingly lighter front trochanters and middle and hind coxae; appressed pubescence present on mesosoma, variably present on first gastral tergite.

Natural History

This is by far the most abundant and widespread species of Paratrechina in Costa Rica. It occurs in lowland rainforest, mangroves, dry forest, and synanthropic habitats. It occurs on the ground or in the canopy, in second growth or mature forest. Workers are in nearly all Winkler samples of sifted litter from the forest floor and in nearly all canopy fogging samples.

Workers are generalized scavengers and recruit to baits.

Nests can be found under stones, in cavities in rotten wood, in small sticks in the leaf litter, in ephemeral stems of large monocots, under epiphytes, and opportunistically in ant plants (e.g., Cordia alliodora). Twice I have found small founding colonies with single queens, and once with two queens. The latter was two physogastric queens in a small stick in the canopy. There were no workers, but one of the queens was guarding brood. In general, I do not find large sprawling colonies with many dealate queens. I suspect this species mainly has small, discrete colonies that are monogynous or with few queens.


What I am interpreting as P. steinheili is quite variable and may represent multiple cryptic species. The main diagnostic feature is the coloration of the coxae. This can vary in degree of contrast. Some workers are pale brown, and the middle and hind coxae are paler but not sharply so. Other workers are dark brown with sharply contrasting bright white middle and hind coxae. Some workers have abundant appressed pubescence on the first gastral tergite. On others have none and the tergite is clear and shiny. The darker, shinier versions tend to be in mature rainforest.

Page author:

John T. Longino, The Evergreen State College, Olympia WA 98505

Date of this version: 19 July 2004.
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