Formicidae, Hymenoptera, Insecta, Arthropoda, Animalia
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Identification
Minor worker: head length 0.56mm, head width 0.48mm, scape length 0.54mm, Webers length 0.64mm (n=1). Head rounded behind, with median notch or excavation; mesonotal suture weakly impressed; propodeal spines moderately long, spiniform; face and mesosoma uniformly foveolate; first gastral tergum mat, not shining; dorsal pilosity sparse (about 8 setae on promesonotum), short, stiff; color yellow.
Major worker: head length 1.08mm, head width 1.00mm, scape length 0.54mm (n=1). Face foveolate throughout, overlain with subparallel, longitudinal rugae on anterior half; clypeus rugose, excavate anteriorly; hypostomal margin gently curved; median tooth rounded, small to absent; pair of stout teeth about one third distance to recessed teeth flanking mandible bases; dorsal pilosity moderately abundant; head with abundant, short setae projecting from sides of head in face view.
Material of this species at the MCZ has been identified as bilimeki Mayr by E. O. Wilson. We disagree with this determination, based on discrepancies with the original description and the distant type locality. The type locality of anastasii is Jimenez/Suerre, very near La Selva Biological Station in Costa Rica. The type description closely matches the species as presented here.
Wilson has also questioned the distinctness of this species and annectens-like specimens. What we are treating as annectens is distinct from and sympatric with anastasii (although occupying different habitats). anastasii minor workers are yellow, and the head is rounded behind with a weak medial impression. The major workers are foveolate on the vertex lobes. anastasii occurs in wet forest understory, where it nests in dead or live plant cavities. In contrast, annectens minor workers are highly variable in color, from yellow to brown, but are usually brown. The posterior border of the head is more flattened and subcordate. The majors are always shiny to some extent on the vertex lobes. annectens occurs in disturbed and synanthropic habitats such as beach edges, roadsides, and around houses. It occurs as a building pest at La Selva Biological Station, with abundant anastasii in the surrounding forest.
Range
Costa Rica, Guatemala. Costa Rica: wet forest areas throughout the country to 1000m elevation (Corcovado, Penas Blancas, La Selva, Tortuguero, Hitoy Cerere).
Natural History
This is a very abundant species in the low arboreal stratum of primary wet forest understory throughout Costa Rica. Nests may be found in almost any kind of cavity or sheltered space, and they may augment their nest space by building galleries and tunnels with carton or earthen construction. Nests have been observed in cavities in live stems of Cephaelis (Rubiaceae) and Pausandra trianae (Euphorbiaceae), bracts of Ischnosiphon (Marantaceae), clasping petiole bases of Araceae, and the bulbous leaf bases of Tillandsia bulbosa. It is a common opportunistic inhabitant of myrmecophytes such as saplings of Cecropia, portions of myrmecophytic Ocotea trees abandoned by Myrmelachista, and myrmecophytic Piper species. In every Costa Rican population of myrmecophytic melastomes (those with petiolar or laminar pouches; Conostegia setosa, Clidemia sp., Tococa sp.) that has been observed (Corcovado, La Selva, Tortuguero), this species has been the most abundant inhabitant. This was the dominant ant in Leanne Tennant's study of Conostegia setosa at La Selva (Tennant 1994). The species also nests in dead sticks and branches on or above the forest floor, and under bark flaps on tree trunks. When nests are in myrmecophytic melastomes, carton galleries may occur on the outside, connecting pouches and extending down the stem to the ground. Colonies appear to be polydomous. Workers are generalist foragers, and may be taken at baits or in samples of sifted leaf litter.
Literature Cited
Tennant, L. 1994. The ecology of Wasmannia auropunctata in primary tropical rainforest in Costa Rica and Panama. Pp. 80-90 in Williams, D.F. [Ed.]. Exotic ants: biology, impact, and control of introduced species. Westview Press, Oxford, England.
Page authors:
John T. Longino, The Evergreen State College, Olympia WA 98505 USA. longinoj@evergreen.edu
Stefan Cover, Museum of Comparative Zoology, Harvard University, Cambridge MA 02138 USA. scover@oeb.harvard.edu
Last modified: 26 November 1997
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