Formicidae, Hymenoptera, Insecta, Arthropoda, Animalia
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Identification
An obligate Cecropia ant.
Workers: scapes and tibiae lack erect hairs; mesonotum with 2-17 hairs (median number 8, n=66); color highly variable between colonies, may be concolorous yellow-brown, bicolored with darker head, or concolorous brown.
Queens: scapes and tibiae lack erect hairs; second gastral tergum with less than or equal to 6 setae, exclusive of posterior row; HL 1.51-1.69mm (median 1.63, n=26); HW 1.24-1.43 (median 1.35, n=26), SL 0.71-0.81 (median 0.77, n=25), WL 2.55-3.05 (median 2.80, n=25), CI 0.778-0.856 (median 0.826, n=26), SI 0.543-0.610 (median 0.573, n=25), GTC 0-5 (median 0, n=80); color usually black.
In many parts of the Neotropics there are two locally sympatric forms in the alfari complex, one of which is less setose than the other. Longino (1989) treated them as two species, with the less setose species being alfari and the more setose species being ovaticeps. The distinction is often clear when members of the alfari complex are locally abundant. For example, in the Atlantic lowlands of Costa Rica, ovaticeps queens have a dense brush of setae on the abdomen, and are conspicuously distinct from alfari in the same area. However, in some areas the distinction is not as clear. In Monteverde, some colonies are identical to standard alfari s.s. from elsewhere in Costa Rica. Other colonies show a range of seta abundances, but are not as densely setose as the Atlantic lowland ovaticeps.
Range
Throughout tropical America from southern Mexico to Northern Argentina.
Natural History
See also general treatment of the Cecropia-Azteca association in Costa Rica.
alfari occurs throughout Costa Rica, and will inhabit any of the myrmecophytic Cecropia species (Longino 1989, 1991b). It generally prefers open and highly disturbed habitats, and may reproduce in relatively small and short-lived trees.
Mature colonies have a dispersed colony structure (Longino 1991a). There is no central carton nest. Brood and any alate sexuals are in branch tips. Older parts of the tree are gradually abandoned, and internal passages are not maintained among occupied branches. Workers are relatively timid and will not defend a mature tree (small saplings are more aggressively defended). When a tree is disturbed, workers usually remain in the branches. Only when a branch is broken open will workers rush out to attack. Trees occupied by alfari often appear somewhat decrepid, with abundant leaf damage and frequently burdened with vines. The foliage of these trees hosts a diverse insect fauna, including foraging ants of other species.
Harada (1989) has described the colony structure of young colonies of alfari. Harada's study did not distinguish between alfari and ovaticeps.
The alfari group, containing alfari and ovaticeps, is a lineage that has colonized Cecropia trees independently of other obligate Cecropia ants (Ayala et al 1996).
Literature Cited
Ayala, F. J., J. K. Wetterer, J. T. Longino, and D. L. Hartl. 1996. Molecular phylogeny of Azteca ants (Hymenoptera: Formicidae) and the colonization of Cecropia trees. Molecular Phylogenetics and Evolution 5:423-428.
Harada, A. Y., 1989, Estrutura de colonias de Azteca alfari Emery (Hymenoptera, Formicidae, Dolichoderinae) em plantas de Cecropia concolor (Moraceae), Revista Brasileira de Entomologia, 33, 169-182.
Longino, J. T. 1989. Taxonomy of the Cecropia-inhabiting ants in the Azteca alfari species group: evidence for two broadly sympatric species. Contributions in Science (Natural History Museum of Los Angeles County) 412:1-16.
Longino, J. T. 1991a. Azteca ants in Cecropia trees: taxonomy, colony structure, and behavior. Pages 271-288 in C. Huxley and D. Cutler, editors. Ant-plant interactions. Oxford University Press, Oxford, U.K.
Longino, J. T. 1991b. Taxonomy of the Cecropia-inhabiting Azteca ants. Journal of Natural History 25:1571-1602.
Page author:
John T. Longino, The Evergreen State College, Olympia WA 98505 USA. longinoj@evergreen.edu
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