Species: Crematogaster bryophilia

Distribution:

Costa Rica, Panama, Venezuela, Ecuador.

Biology:

Crematogaster bryophilia prefers montane wet forest habitats, where it nests in mature forest canopy. It nests in dead branches but unlike most Crematogaster species also frequently nests beneath epiphyte mats. Most collections of C. bryophilia that I have observed are from the Atlantic slope of Costa Rica. At La Selva Biological Station, in lowland rainforest, it is relatively rare. It occurred in 7 of 52 canopy fogging events, and I have only once found it there by manual search (a nest was in a thin dead branch of a tall Erythrina tree [Fabaceae]). Upslope from La Selva in Braulio Carrillo National Park I collected a nest that was 20m high in a Licania tree (Chrysobalanaceae). There was a moss-covered branch and along the branch was a patch of flat, pale green lichen. Beneath this lichen patch were a single colony queen, most of the workers, and all of the brood. Workers occurred in galleries beneath the moss, extending about one half meter to each side of the lichen patch. I did not see any workers on the surface of the moss mat or on foliage. Perhaps the lichen provided an improved microhabitat, being warmer and drier than the surrounding moss. Near Turrialba I found an aggregation of workers, brood, and alate queens under a bark flap on a Psidium guajava tree (Myrtaceae) in a brushy pasture at the edge of mature forest. The workers were foraging in columns on the Psidium trunk and branches. In the Pe?as Blancas Valley east of Monteverde, a montane wet forest site at 800m elevation, I have collected the species on over five occasions. I observed one nest in a thin dead branch, several in internodes of Cecropia insignis saplings (Cecropiaceae), one in the hollow stem of a small Guarea (Meliaceae), and one under an epiphyte clump in a recently felled Licaria tree (Lauraceae). I found nests under epiphyte mats at Estacion Cacao in Guanacaste Conservation Area and at Sirena in Corcovado National Park. Nests may contain alate queens and tiny pale males. Twice I have found ergatogynes, once alone in a nest with workers, and once along with a single physogastric colony queen.

Beyond Costa Rica I have records of collections from montane areas in Panama, Venezuela, and Ecuador. The specimens from Venezuela were intercepted with orchids at a U. S. quarantine station, suggesting association with epiphytes.

This species is infrequent in collections, and most of my collections have been by discovering nests, finding workers in fresh treefalls, or finding nocturnal foragers. It is not among the species routinely found in baiting studies, sweep samples, or Malaise traps. Yet my nest collections are relatively frequent, suggesting the species can be common if you know where to look. It is a habitat and elevational specialist, perhaps a largely nocturnal forager, and perhaps doing much of its foraging under epiphytes, all factors contributing to its apparent rarity.