Formicinae, Formicidae, Hymenoptera, Insecta, Arthropoda, Animalia
Additional images: minor worker, dorsal view of propodeum showing anterolateral spines and mesonotal crest (reduced, original).
Mexico to Argentina. Costa Rica: lowland to mid elevation areas throughout the country.
Minor worker: anterolateral margins of pronotum with projecting tubercles; mesonotum and propodeum with continuous median longitudinal carina; body covered with a dense layer of long appressed pubescence, usually bright gold in color but sometimes silver; in the field they are conspicuously yellow ants.
This is the largest and most conspicuous Camponotus species in Costa Rica. It inhabits dry forest or wet forest habitats, but seems to be more abundant in the more seasonal areas on the Pacific side. The workers are diurnal and are generalist scavengers. They often visit extrafloral nectaries.
Nests are in cavities in the trunks or large branches of large, live trees. I have not seen the inside of a nest (you would need to follow a logging operation to do this very often) but I have seen workers entering and exiting small apertures in the live trunks of giant rainforest trees, with major workers standing guard around the aperture. During three years of field work in Corcovado National Park, I often walked by a large tree that was continuously occupied by a C. sericeiventris nest. I presume colonies are long-lived, with long residence times in their well-protected nest sites.
In Corcovado, I once observed what appeared to be a synchronous nuptial flight by C. sericeiventris. On 19 August 1982, as I walked through the forest around Sirena, I observed many alate queens on all parts of my several kilometer route. At one point I found many alates emerging from a nest in a recently fallen tree. They seemed to be very poor fliers.
Injured workers are prone to attack by phorid flies. Three times at Corcovado National Park I observed injured workers on the forest floor being attacked by phorids. The workers were missing tarsi and parts of their antennae, as though from fights with other ants. Small clouds of phorids were hovering around the injured ants, periodically diving and attacking. The ants were highly agitated, jerking and snapping at the flies. One of these observations was particularly dramatic. One worker had the head and alitrunk of another worker clamped to its leg and was frantically trying to escape. Two Odontomachus were attacking the pair, and all the time the phorids were hovering nearby.
I once observed a worker on a Passiflora shoot doing a special "rain walk." It was raining steadily, and the ant moved up and down the stem with its legs completely encircling the stem, body closely appressed, and moving very slowly.
Guerin-Meneville, F. E.. 1838. Histoire naturelle des crustaces, arachnides et insectes. L. I. Duperrey, Voyage autour du monde, execute par ordre du Roi, sur la corvette de Sa Majeste, La Coquille, pendent les annees 1822, 1823, 1824 et 1825. Zoologie 2. , Paris. 319 pp.
John T. Longino, The Evergreen State College, Olympia WA 98505 USA.email@example.com
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