Dolichoderinae, Formicidae, Hymenoptera, Insecta, Arthropoda, Animalia
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Additional images:
Queen, mandible (large), petiole, posterior view of sternal lobe (large), petiole, lateral view (small, large), tibia (small, large).
Worker, mandible (small, large), petiole, lateral view (small, large), tibia (small, large).
Range
Central Mexico to northern Argentina. Costa Rica: widespread.
Identification
Queen
Measurements (n=21): HLA 1.62 (1.51-1.69), HW 1.32 (1.26-1.43), SL 0.76 (0.71-0.85), CI 83 (80-86), SI 47 (45-51).
Palpal formula 5,3; middle and hind tibia with prominent pectinate apical spur; dorsal surface of mandible largely smooth, with sparse small piligerous puncta, setae in puncta short, larger puncta with long setae near masticatory margin; medial and lateral clypeal lobes at about same level (medial lobe not projecting anteriorly); head weakly quadrate; petiolar node acute, triangular, neither strongly flattened nor bluntly rounded; posteroventral petiolar lobe well-developed, evenly convex; scape and tibia lacking setae, sides of head lacking setae, posterior margin of head with abundant curved setae, pronotum with posterior row of curved setae, mesoscutum with sparse setae, scutellum and propodeum with more abundant setae, petiolar node with cluster of erect setae, third abdominal tergum with abundant erect setae, fourth and fifth abdominal terga with 0-6 erect setae exclusive of posterior row; color light red brown to black.
Worker
Measurements (n=13): HLA 0.99 (0.80-1.24), HW 0.88 (0.72-1.07), SL 0.60 (0.53-0.72), CI 91 (86-94), SI 62 (58-69).
Palpal formula 5,3; middle and hind tibia with prominent pectinate apical spur; dorsal surface of mandible largely smooth, with sparse small piligerous puncta, setae in puncta short, larger puncta with long setae near masticatory margin; medial and lateral clypeal lobes at about same level, medial lobe at most weakly projecting beyond lateral lobes; head with convex sides, strongly cordate posterior margin; mesosoma in lateral profile with promesonotum forming a continuous convexity or mesonotum somewhat elevated above pronotum; posterior mesonotum drops gradually to narrow metanotal groove such that posterior mesonotum, metanotal groove, and dorsal face of propodeum form a broad, shallow V (dorsal face of propodeum and broad metanotal groove do not form flat, step-like junction with posterior mesonotum); scape and tibia lacking setae, sides of head lacking setae, posterior margin of head with sparse to abundant erect setae, pronotum, mesonotum, and dorsal face of propodeum with conspicuous erect setae, mesonotum usually with about 8 erect setae of relatively uniform length (range 2-17; contrast with A. ovaticeps); color brown to yellow.
Similar Species
Azteca alfari is most similar to A. ovaticeps (Longino 1989a). See differentiating characters in key and under A. ovaticeps. Workers of A. alfari may also be confused with workers of A. forelii. Mandibles of A. alfari workers are smooth and shiny; mandibles of A. forelii workers are roughened and dull.
Natural History
The taxonomy and biology of A. alfari are reviewed in Longino (1989a, 1991b). Also see review of Azteca-Cecropia ant-plant relationship.
Azteca alfari is an obligate Cecropia ant. It is the most widespread of the Cecropia ants, extending into the subtropics at both ends of its range. Throughout the range it is the Cecropia ant most likely to be found in open or highly disturbed areas. Founding queens are frequent in Cecropia saplings. As trees grow and form multiple branches, the nests become polydomous. Workers and brood are dispersed in branch tips, and the bole and inner portions of branches are progressively abandoned (Longino 1991a). Workers vary in aggressiveness geographically and over time. Workers in young colonies are usually aggressive, but in many cases workers in mature colonies are less aggressive, retreating inside of stems on disturbance (Longino 1991a). 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).
Page author:
John T. Longino, The Evergreen State College, Olympia WA 98505 USA. longinoj@evergreen.edu
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