Pachycondyla harpax

A common species with a wide range, it can be found in North, Central, and South America.

Identification
From Mackay and Mackay (2010): Pachycondyla harpax is the most common species in the New World and is also widely distributed. The worker can be separated from most other species in the genus as it lacks the malar carina and the eye is small but is located less than one maximum diameter from the anterior edge of the head (side view). The pronotal carina is poorly developed but forms a shiny raised line (usually), the metanotal suture is absent on the dorsum of the mesosoma and the petiole is rectangular shaped with a distinct dorsal face and the posterior lateral margin forms a sharp carina, which is barely evident as it passes to the anterior edge of the petiole. The anterior face of the postpetiole forms a right angle with the dorsal face, which may be slightly concave.

The sharply angulate anterior face of the postpetiole of P. harpax could cause confusion with Pachycondyla procidua, but they can be easily separated as the metanotal suture of P. procidua breaks the sculpture and the petiole of P. procidua has a vertical anterior face and broadly rounded posterior face, which meet near the anterior edge of the apex of the petiole in a sharp angle. The basically rectangular-shaped petiole of P. harpax could cause confusion with Pachycondyla crassinoda, Pachycondyla striata,  and Pachycondyla impressa. Pachycondyla harpax can be easily separated from all three of these species by its much smaller size (the workers of the other three species are usually at least 10 mm in total length). Pachycondyla harpax can be separated from smaller specimens of P. impressa, as the pronotal carina is present, at least as a shiny raised line, not nearly rounded as in P. impressa. It lacks the clypeal carina found in Pachycondyla lenis of Brasil and although the pronotal carina is poorly developed, it is still obvious (nearly always) at least as a shiny raised line against the dull sculpture, not completely absent as in P. lenis.

John Longino refers to specimens which lack the pronotal carina as JTL-003. All specimens from the southern Pacific lowlands (Osa Peninsula) lack the carina, everywhere else in Costa Rica they have it (Longino, pers. comm.). They are not sympatric with the “normal” P. harpax and may represent a separate species. Longino also has a collection of this phenotype from the state of Barinas, Venezuela. We will recognize them as only a minor geographic variant in this revision.

Distribution
Southern United States through South America, Trinidad, Grenada, Jamaica. (Mackay and Mackay 2010)

This taxon was described from South America.

Habitat
These ants are found in a wide variety of habitats, ranging from dry forest, late dry season gap forest, urban environments, parks, grassy areas, coffee, cacao and banana plantations, cypress swamps, to oak forests, oak riparian forests, rocky wet quebradas [streams], arid scrub, palm thorn forests, tropical deciduous forests, tropical evergreen forests, second growth tropical forests, transitional bamboo/cloud forest, old growth dry tropical forest, steep rocky forest slopes, ridge forest, wet mountain forests, riparian rain forest, montane evergreen forest, lowland forests, cloud forest and riparian tropical rain forests. This species has been collected in caves near the entrances (Reddell and Cokendolpher, 2001). They occur from sea level to 2000 meters. (Mackay and Mackay 2010)

Biology
From Mackay and Mackay (2010): Nests are found in the soil often under stones (Buckley, 1866) or pieces of wood, or in rotten logs, in organic matter on top of rotten logs and under cow dung (Pergande, 1895). Logs may be very large (1+ meter diameter, 2+ meters long); stones may be very heavy (200+ kg). Soils vary from clays to sandy gravel. A nest gyne was found at a soil depth of 50 cms. One nest was found in the abandoned nest of the native fire ant Solenopsis geminata. They can nest in a wide variety of soils ranging from clay to sand. Workers are commonly collected in Winkler extractions and in pitfall traps. Brood was found in nests in July (Guatemala), August (USA) and November (Colombia). Sexuals were found in nests in February (Bolivia), March to June (Texas, Mexico, Ecuador), April (México) and November (Colombia). Alate females have been collected in February (Perú) and April (Texas, Costa Rica). Dealate females have been collected in May (Mexico), June (Mexico, Costa Rica, Colombia), July to September (Mexico, Colombia), August (USA, Ecuador), October (USA, Venezuela, Bolivia) and December (México, Colombia). Loose males have been collected in January (México), February (Ecuador), April (USA), July (México, El Salvador), between January and July (Ecuador, canopy fogging), August (México), October (Panamá) and November (México) and December (México, Costa Rica). The nests have multiple ergatomorphic females (Wheeler, 1900).

Workers are predaceous (Maes, 1989) and forage primarily on the ground. They can be collected in surface traps baited with mealworms or tuna and pitfall traps. A few workers have been collected in baits hanging in the vegetation, especially trees. This species preys on worker termites (Gnathamitermes tubiformans) in northern México (Garcia-Pérez et al., 1977). Workers are alert and fast and normally not very aggressive when the nest is disturbed. Wheeler (1900) describes interesting worker behavior: they fold their antennae and “peep out” of holes and crevices in the soil “like a rat”. Workers produce foam from the tip of the gaster (Maschwitz et al., 1981; Overal, 1987), similar to workers of Pachycondyla striata.

These ants are found in the same areas as Pachycondyla apicalis and one nest was in the refuse of an Atta mexicana nest. Baena (1993) reported that P. harpax nests together with ants of the genus Leptogenys. Foragers disperse the seeds of Calathea ovandensis (Marantaceae) approximately 75 cm from where they are collected (Horvitz and Schemske, 1986b).

This species is parasitized by a phorid fly Metopina pachycondylae (see Wheeler and Wheeler, 1952 for a survey of the literature) as well as Apocephalus sp.

Hung and Vinson (1975) describe the male reproductive system.

Nomenclature

 *  harpax. Formica harpax Fabricius, 1804: 401 (w.) SOUTH AMERICA. Wheeler, W.M. 1900b: 4, 17 (q.m.l.); Wheeler, G.C. & Wheeler, J. 1952c: 618 (l.). Combination in Pachycondyla: Roger, 1863b: 18. Senior synonym of concinna, dibullana, irina, montezumia (and its junior synonyms amplinoda, orizabana): Brown, 1950e: 247. See also: Mackay & Mackay, 2010: 374.
 * montezumia. Pachycondyla montezumia Smith, F. 1858b: 108 (q.m.) MEXICO. Forel, 1899c: 12 (w.); Wheeler, G.C. & Wheeler, J. 1952c: 618 (l.). Junior synonym of harpax: Roger, 1862c: 288; Roger, 1863b: 18; Dalla Torre, 1893: 34. Revived from synonym as subspecies of harpax: Forel, 1899c: 12; Emery, 1911d: 75. Senior synonym of amplinoda, orizabana: Emery, 1911d: 75. Junior synonym of harpax: Brown, 1950e: 247.
 * amplinoda. Ponera amplinoda Buckley, 1866: 171 (w.) U.S.A. Junior synonym of harpax: Emery, 1895c: 266; of villosa: Forel, 1899c: 14; of montezumia: Emery, 1911d: 75.
 * dibullana. Pachycondyla harpax var. dibullana Forel, 1901f: 347 (w.) COLOMBIA. Forel, 1912c: 39 (q.). Junior synonym of harpax: Brown, 1950e: 247.
 * concinna. Pachycondyla harpax var. concinna Wheeler, W.M. 1925a: 5 (w.q.) BRAZIL. Junior synonym of harpax: Brown, 1950e: 247.
 * irina. Pachycondyla harpax var. irina Wheeler, W.M. 1925a: 5 (w.) GUATEMALA. Junior synonym of harpax: Brown, 1950e: 247.

Worker
From Mackay and Mackay (2010): The workers are moderately large (total length up to 10 mm) black ants with dark brown appendages. The mandibles have 9 or 10 teeth; the anterior border of the clypeus is usually convex, although it may be nearly straight or even slightly concave medially. The central region of the clypeus is swollen and may even form a longitudinal carina posteriorly. The region anterior to the eye is without a malar carina, although it may be slightly raised. The eyes are relatively large (0.34 mm maximum diameter) and are separated from the insertion of the mandibles by less than one maximum diameter (side view). The scape extends only slightly past the posterior lateral corner of the head. The pronotal shoulder is nearly always formed into a definite carina, which passes forward on the anterior lateral surface of the pronotum. The metanotal suture is absent on the dorsum of the mesosoma or is only slightly developed. The petiole is rectangular-shaped with the anterior and posterior faces being nearly parallel, the posterior surface forming definite bend with the dorsal surface. Posteriorly the petiole has sharp lateral borders which define the posterior face. The anterior face of the post-petiole may be slightly concave.

Erect hairs are abundant on most surfaces, including the mandibles, clypeus, scapes, dorsum of the head, region near the eyes, ventral surface of the head, dorsum of the mesosoma, petiole and all surfaces of the gaster, the hairs on the tibiae are mostly suberect. Appressed golden pubescence is abundant on most surfaces.

The mandibles are smooth and glossy with scattered punctures, most of the dorsum of the head is covered with dense punctures, as is the mesosoma and petiole, the punctures on the dorsum of the gaster are more scattered and much of the gaster is smooth and glossy.

Queen
From Mackay and Mackay (2010): The female is slightly larger (total length over 10 mm) and is similar to the worker except the mesosoma is more massive and some structures, especially the side of the pronotum, mesopleuron and the side of the propodeum, are striate. The metanotal suture is well developed, forming a definite metanotum. The wing has the typical venation of members of the genus.

Erect hairs are abundant on essentially all of the surfaces, including the mandibles, dorsal and ventral surfaces of the head, sides of the head, clypeus, scapes (often longer than the diameter of the scape), mesosoma, petiole and gaster. Fine golden appressed pubescence is present on all surfaces except the mandibles and is especially obvious on the head and gaster.

The mandibles are finely sculptured and mostly smooth and glossy, the head and mesosoma are densely punctured and weakly shining, the gaster is finely punctured and moderately smooth and glossy.

Male
From Mackay and Mackay (2010): The male is also a moderate sized specimen (total length about 9 mm) black with brown legs. The eye is large, covering more than half of the side of the head. The pronotal carina, which is well developed in both the worker and female, is lacking. The metanotal suture is well developed, as is the metanotum. The petiole is somewhat rectangular shaped but is definitely narrowed toward the apex, with a rounded node (not developed into a definite dorsal surface). The posterior face of the petiole is not defined by a carina. There is considerable variability in the shape of the subpetiolar process.

Erect hairs are abundant and scattered on most surfaces; the hairs on the tibiae are mostly suberect.

Most surfaces are coriaceous and at least weakly shining, although most of the surface is hidden by appressed golden pubescence.

Type Material
Lectotype worker, 3 paralectotype workers, 3 paralectotype females here designated, ; 3 syntypes seen, ; two syntype workers seen,, 3 syntypes workers, , 6 worker syntypes , 5 worker cotypes, 1 female cotype (Mackay and Mackay 2010)

Type Locality Information
South America; México; central Texas; México, locality not specified, presumably Orizaba; Colombia, Dibulla; Brasil: Rio Madeira, Abuná; Guatemala, Escuintla (Mackay and Mackay 2010)

Etymology
The name of this species may be based on the Latin word harpe, meaning sword and possibly referring to the sting. (Mackay and Mackay 2010)

Additional References

 * Baena, M. L. 1993. Hormigas cazadoras del género Pachycondyla (Hymenoptera: Ponerinae) de la Isla Gorgona y la planicie Pacifica Colombiana. Boletin. Del Museo. Entomológica de la Universidad del Valle 1:13-21.


 * Buckley, S. B. 1866. Descriptions of new species of North American FORMICIDAE. Proceedings of the Entomological Society of Philadelphia. 6:152-172.


 * Fabricius, J. C. 1804. Systema Piezatorum. 439 pp. Brunsvigae.


 * García-Pérez, J., A. Blanco-Piñón, R. Mercado-Hernández and M. Badii. 1977. El comportamiento depredador de Pachycondyla harpax Fabr. sobre Gnathamitermes tubiformans Buckley en condiciones de cautiverio. Southwestern Entomologist 22:345-353.


 * Horvitz, C. C. and D. Schemske. 1986. Ant-nest soil and seedling growth in a Neotropical ant-dispersed herb. Oecologia 70:318-320.


 * Hung, A. C. and S. B. Vinson. 1975. Notes on the male reproductive system in ants (Hymenoptera: Formicidae). Journal of the New York Entomological Society 83:192-197.




 * Maes, J.-M. 1989. Catálogo de los insectos controladores Biológicas en Nicaragua. Volumen I. Insectos depredadores (Primera parte). Revista Nicaraguense de Entomología 8:1-106.


 * Maschwitz, U., Jessen, K. and Maschwitz, E. 1981. Foaming in Pachycondyla: a new defense mechanism in ants. Behavioral Ecology and Sociobiology 9:79-81.


 * Overal, W. L. 1987. Defensive chemical weaponry in the ant Pachycondyla harpax (Formicidae: Ponerinae). Journal of Entomological Science 22:268-269.


 * Pergande, T. 1895. Mexican Formicidae. Proceedings of the California Academy of Sciences 5:858-896.


 * Wheeler, G. C. and J. Wheeler. 1952. The ant larvae of the subfamily Ponerinae - Part II. American Midland Naturalist 48:604-672 [including 6 plates].


 * Wheeler, W. M. 1900. A study of some Texas Ponerinae. Biological Bulletin 2:1-31 + 10 Figures.