Azteca gnava Forel

Longino, J. T., 2007, A taxonomic review of the genus Azteca (Hymenoptera: Formicidae) in Costa Rica and a global revision of the aurita group., Zootaxa 1491, pp. 1-63 : 34-35

Azteca gnava Forel 1906

Figures 3,4A,5,6E,6F.

Azteca paraensis subsp. gnava Forel 1906:241. Syntype workers: Costa Rica (Biolley) (in an abandoned termite nest) ; and " Surubrés, touffe d'orchidée, dans un nid de termites"; and " San Mateo , racines de goyavier (le meme)" [ MHNG] (examined, one Costa Rica (Biolley) worker here designated LECTOTYPE).

Azteca paraensis subsp. gnava var. surubrensis Forel 1908a:62 (unavailable name). Syntype workers: Costa Rica, Surubres and El Hiquito near San Mateo (Biolley), dans des racines de goyaviers [ MHNG] (examined).

Azteca gnava Forel ; Forel 1912:49.

Azteca gnava surubrensis Forel 1912:49 (first available use of surubrensis Forel 1908) [MHNG] (examined). NEW SYNONYMY

Azteca ulei subsp. rossi Forel 1909:251. Syntype workers: Mexico, amongst orchids in antgarden (Ross) [ MHNG] (examined). NEW SYNONYMY

Queen characters. Measurements (n=5): HLA 2.19 (2.18-2.20), HW 2.37 (2.33-2.47), SL 1.14 (1.11-1.20), CI 108 (107-113), SI 52 (50-55).

Palpal formula 6,4; ocelli small; middle and hind tibia with prominent pectinate apical spur; dorsal surface of mandible with abundant piligerous puncta, setae in puncta a combination of longer erect setae and shorter subdecumbent setae, interspaces between puncta faintly microareolate with varying development of roughened, acicular sculpture; medial and lateral clypeal lobes at about same level; head with convex sides, posterior margin strongly cordate; petiolar node in lateral view varying from triangular to flattened and scale-like at apex; posteroventral lobe of petiole deep, with posterior margin forming a concave or vertical surface, meeting tergum anterior to posterior limit of posterior tergal lobe (Fig. 1D, 5); scape with abundant erect setae, about as long as one half to two thirds maximum width of scape; middle and hind tibia with abundant erect setae, longest of these about as long as one half maximum width of tibia (MTSC 20-40); side of head with 0- 1 erect setae near mandibular insertion, lacking elsewhere; posterior margin of head with abundant long erect setae; pronotum with erect setae on anterior margin and posterior margin, leaving bare space medially; mesoscutum, scutellum, and propodeum with abundant erect setae; petiolar node rimmed with erect pubescence and irregular longer erect setae, 2-3 pairs of erect setae usually extending above apex in profile, posterior border of sternal lobe of petiole with dense layer of erect setae of irregular lengths; gastral terga with moderately abundant long erect setae; almost entire body uniform dark red brown, lighter orange brown around antennal fossa.

Worker characters. Measurements (n=14): HLA 1.24 (1.00-1.44), HW 1.29 (1.01-1.47), SL 0.94 (0.81- 1.01), CI 105 (101-109), SI 77 (70-85).

Palpal formula 6,4; middle and hind tibia with prominent pectinate apical spur; dorsal surface of mandible smooth and shining near masticatory margin, grading to microareolate and dull at base, with moderately abundant small piligerous puncta, setae in puncta short, erect, larger puncta with long setae near masticatory margin; medial and lateral clypeal lobes at about same level; head with strongly convex sides, strongly cordate posterior margin; in lateral profile pronotum evenly sloping, slightly convex, mesonotum more strongly convex, forming separate convexity; posteroventral lobe of petiole well developed, deep; scape with abundant erect setae, length of setae about one half to equal to maximum width of scape; mid and hind tibia with abundant erect setae, longest setae about one half to two thirds maximum width of tibia; side of head with 2-5 erect setae irregularly distributed along side; posterior margin of head with abundant long erect setae; pronotum, mesonotum, and dorsal face of propodeum with abundant long setae, those on dorsal face of propodeum sometimes shorter, sparser, less erect than those on pronotum and mesonotum; most of body light to dark brown.

Similar species. The queens of A. gnava are most similar in size and shape to queens of A. instabilis and A. sericeasur . They differ from A. instabilis by the small ocelli (OCW <0.15 for A. gnava ,> 0.20 for A. instabilis ), and from A. sericeasur by the uniformly brown face (with extensive yellow coloration on A. sericeasur ). Azteca gnava differs from both species in the deep posteroventral petiolar lobe, with vertical to concave posterior face. Workers of A. gnava are difficult to distinguish from A. velox and A. nigra . They tend to be somewhat larger than both. The ventral petiolar lobe is more strongly developed than A. velox , and the scapes tend to be relatively shorter than A. nigra (Fig. 6F).

Range. Southern Mexico to Panama.

Biology. Azteca gnava occurs in the canopy of wet to moist forest habitats, where it forms ant gardens. Ant gardens are moderately abundant in Costa Rica, usually in the canopy of wet to moist forest, and often in trees overhanging streams or river margins. Costa Rican ant gardens are formed by a number of species, including Odontomachus panamensis (in parabiotic association with Crematogaster carinata ), C. jardinero , C. longispina , Pheidole violacea , Azteca gnava , and A. nigra .

Azteca gnava ant gardens are large and their associated epiphytes usually appear dense and well established(e.g. robust Aechmea (Bromeliaceae) plants, dense mats of Peperomia (Piperaceae), hemiepiphytic Coussapoa ). In Corcovado National Park, Costa Rica, A. gnava ant gardens often have abundant growth of Peperomia macrostachya and Aechmea tillandsioides var. kienastii . Colonies usually occur as one or more large central nests and numerous smaller satellite nests, forming an "archipelago" of ant gardens. Larger nests may be over 50cm diameter. Invariably, large populations of coccoid Hemiptera are sheltered beneath the ant gardens, attached to the supporting branch of the host tree and sometimes on the epiphytes on the nest. Ant brood can be found dispersed throughout the gardens.

Queens were unknown prior to this study and they are very rarely encountered. In the one case in which I observed a colony queen, it inhabited the central and largest ant garden. Very occasionally alate queens are taken in Malaise traps. On Barro Colorado Island, Panama, I collected an alate queen flying in the forest at 1700hrs.

Comments. Azteca gnava may be close to or the same as A. ulei , the ants from Ule's classic studies of Amazonian ant gardens (Ule 1901).

Additional material examined. COSTA RICA: Alajuela: Atenas , Nov 1977 (L. D. Gómez P.) - workers[ USNM] ; Heredia: 11km ESE La Virgen , 10°21'N, 84°03'W, 300m , Feb - Apr 2004 (ALAS) - alate queen ; Limon: Hamburg Farm , 10°15'N, 83°27'W, 50m , 28 Nov 1925 (F. Nevermann) - workers [ USNM] ; Tortuguero , 10°32'N, 83°31'W, 5m , 5 Jul 1985 (J. Longino) - workers, dealate queen ; 10km ESE Moravia , 9°48'N, 83°22'W, 500m , 28 Aug 1985 (J. Longino) - workers ; Hitoy Cerere Biol. Reserve , 9°40'N, 83°02'W, 100m , 1 Sep 1985 (J. Longino) - workers ; Puntarenas: Sirena, Corcovado National Park , 8°29'N, 83°36'W, 5m , multiple collections and dates (J. Longino) - workers ; same locality, 1- 30 Apr 1992 (G. Rodriguez) - alate queen [ INBC] ; Llorona, Corcovado National Park , 8°35'N, 83°42'W, 5m , 8 Jun 1982 (J. Longino) - workers ; Rio Nino , Corcovado National Park , 8°33'N, 83°29'W, 300m , 11 Feb 1996 (J. Longino) - workers, males ; 5km SW Las Alturas , 8°55'N, 82°52'W, 1240m , 24 Mar 1990 (J. Longino) - worker (tentative determination) ; 19km S Ciudad Neily , 8°29'N, 82°58'W, 20m , 25 Mar 1990 (J. Longino) - workers, male ; Rancho Quemado, Osa Peninsula , 8°42'N, 83°33'W, 200m , 1- 30 Nov 1991 (F. Quesada) - alate queen [ INBC] ; same locality, 1- 30 Apr 1992 (K. F. Flores) - alate queen [ INBC] ; GUATEMALA: Izabal: Livingston , 15°50'N, 88°45'W (Schwarz & Barber) - alate queen [ USNM] ; HONDURAS: Comayagua: 1mi W. Taulabe , 1990 (C. Catton) - worker ; PANAMA: Canal Zone: Barro Colorado Island , 9°09'N, 79°51'W, 100m , 4 Jul 1997 (J. Longino) - alate queen .