Dolichoderinae, Formicidae, Hymenoptera, Insecta, Arthropoda, Animalia
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Additional images:
Guacimal:
Worker:
face view (original line drawing),
mesosoma, lateral view (original line drawing).
Queen:
face view (original line drawing, reduced line drawing).
La Selva:
Worker:
face view (small, large),
lateral view (small, large).
Queen:
face view (small, large),
lateral view (small, large),
propodeum (original line drawing, reduced line drawing).
Monteverde:
Worker:
face view (original line drawing, reduced line drawing),
mesosoma, lateral view (original line drawing, reduced line drawing).
Queen:
face view (small, large, original line drawing),
mandible (original line drawing, reduced line drawing),
propodeum (original line drawing, reduced line drawing),
petiole, lateral view (small, large, original line drawing, reduced line drawing).
Palmar:
Queen:
face view (small, large),
lateral view (small, large).
JTL-007:
Worker:
face view (small, large),
lateral view (small, large).
Queen:
face view (small, large),
lateral view (small, large).
Range
Mexico to Panama. Costa Rica: widespread.
Identification
Queen
Measurements (n=64): HLA 1.48 (1.29-1.68, 62), HW 1.02 (0.83-1.14), SL 0.65 (0.59-0.72, 13), CI 68 (63-74, 62), SI 44 (42-45, 13).
Palpal formula 5,3; middle and hind tibia with prominent pectinate apical spur; dorsal surface of mandible with row of large puncta at masticatory margin, these bearing long setae, otherwise puncta small and lacking setae, surface smooth and shiny over variable extent of surface, becoming faintly microareolate and dull toward base; medial and lateral clypeal lobes at about same level; head rectangular, posterior margin distinctly excised medially; petiolar node short, bluntly rounded; posteroventral petiolar lobe moderately convex from front to back; scape with moderately abundant erect setae, about as long as one half maximum width of scape; middle and hind tibia with moderately abundant erect setae, longest about as long as one third maximum width of tibia (MTSC 5-15), side of head with 0-5 short erect setae near mandibular insertion, lacking setae elsewhere, posterior margin of head with abundant short setae; pronotum with posterior row of erect setae, mesoscutum and propodeum with sparse to abundant erect setae, scutellum with abundant erect setae, petiolar node in profile with 4-8 pairs erect setae projecting above apex, posteroventral lobe with abundant short erect setae; gastral terga with sparse erect setae; general body color uniformly dark brown.
Worker
Measurements (n=28): HLA 1.01 (0.77-1.21), HW 0.84 (0.64-0.99), SL 0.53 (0.44-0.60), CI 0.83 (0.78-0.89), SI 0.54 (0.49-0.60).
Palpal formula 5,3; middle and hind tibia with prominent pectinate apical spur; dorsal surface of mandible smooth and shiny, row of large puncta along masticatory margin with setae, others small and lacking setae; medial and lateral clypeal lobes at about same level; head elongate with weakly convex sides, strongly excavate posterior margin; in lateral profile pronotum shallowly convex, mesonotum slightly more convex and forming slightly separate convexity; scape with moderately abundant, inconspicuous erect setae, length of setae about one half maximum width of scape; mid and hind tibia with moderately abundant erect setae, longest about one half maximum width of tibia; side of head with 2-5 short erect setae anterior to eye, lacking setae elsewhere; posterior margin of head with abundant short erect setae; pronotum, mesonotum, and dorsal face of propodeum with abundant erect setae; color brown.
Similar Species
The 5,3 palpal formula, the presence of tibial spurs, and the elongate rectangular head places A. pittieri among the species treated in Longino (1996). The lack of conspicuous erect setae on the mandibles differentiates it from A. brevis and A. nigricans. The remaining similar species are A. beltii, A. oecocordia, and A. longiceps. Queens of A. pittieri differ from queens of A. beltii in the smaller size and brown color. They differ from A. longiceps and A. oecocordia in the relatively shorter, less rectangular head.
Natural History
The taxonomy and biology of this species is reviewed in Longino (1996). More recent studies of the relationship between Cordia alliodora and Azteca pittieri are Tillberg (2004), and Trager & Bruna (2006).
This species is the dominant inhabitant of the ant plant Cordia alliodora. Most Cordia alliodora plants in Costa Rica harbor colonies of A. pittieri. Founding queens can be found alone in Cordia nodes and never seem to found pleometrotically. Colonies are apparently monogynous, with workers, brood, and coccoid Hemiptera dispersed in nodes throughout the tree. Workers are aggressive and forage on the surface of the host tree, but do not generally forage off the host tree.
A set of collections of A. pittieri have been made from understory Lauraceae. I collected workers from small trees (either Ocotea or Licaria) at Tortuguero, and workers and alate queens from Ocotea nicaraguensis at Carara Biological Reserve. These were dispersed in live branch tips, with general colony structure and behavior much like the colonies in Cordia. INBio Parataxonomists collected isolated queens at Rancho Quemado on the Osa Peninsula.
Comments
The collections from Lauraceae are probably a distinct species, and I use the morphospecies code JTL-007 for them, but I cannot identify any morphological characters that distinguish them from the Cordia-inhabiting A. pittieri. The mandibles tend to be somewhat more setose, with larger and more abundant piligerous puncta compared to the specimens from Cordia. On some workers there are a few short setae on the side of the head posterior to eye, and the general surface pubescence is more abundant and longer. All other characters fall well within the range of variation for the Cordia specimens.
In Costa Rica, the queens of the Cordia-inhabiting A. pittieri cluster into two size classes (Fig. 4B). Smaller queens are from the Pacific lowlands, up to about 500m elevation. Larger queens occur at higher elevations on the Pacific slope, throughout the Atlantic lowlands of Costa Rica, and the scattered collections from further north in Central America and southern Mexico, including the type of A. patruelis (synonymized under pittieri in Longino [2007]). Given that the two forms are parapatric and appear to have identical natural history, I am reluctant to consider them distinct species until additional collections and characters are examined.
Variation in queen propodeal pilosity is discordant with head shape. Queens from the Pacific side of Costa Rica, regardless of queen head shape, have dense pilosity on the propodeum. Queens from La Selva on the Atlantic slope have sparser propodeal pilosity, and it varies from a uniform covering to a discontinuous covering, with a few setae near the mesopropodeal suture, a gap with no setae, and a cluster of setae posterior to the spiracle. La Selva queens with the relatively shortest heads are indistinguishable from two queens collected from Hone Creek south of Limon, and these relatively small queens exhibit the extreme of propodeal pilosity reduction. Relatively larger queens tend to have more uniform propodeal pilosity.
The types of A. patruelis were sent to Forel by Wheeler, and Wheeler (1942:15) provided additional notes on the specimens. They were sent to Wheeler by C. H. Tyler Townsend, who collected them near Cualata, on the slopes of Volc‡n de Colima, Mexico, in Cordia alliodora. The ants kept large red lecanoid coccids in the nest.
Page author:
John T. Longino, The Evergreen State College, Olympia WA 98505 USA. longinoj@evergreen.edu
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