Southern Mexico to Paraguay. Costa Rica: widespread in Atlantic and Pacific slope wet forest, sea level to at least 1200m.
In wet forested habitats of Costa Rica, this is one of the most common and conspicuous ants. Foraging workers are extremely fast and run over the surface of trails in a nervous, erratic manner, with the antennae rapidly vibrating. Their behavior is reminiscent of pompilid wasps. Foragers are solitary hunters on the ground, where they capture live prey. They are never arboreal. I have only seen diurnal foragers; I do not think they forage at night. Nests are in dead wood.
Colonies typically have a reproductive queen, but workers exhibit dominance hierarchies among themselves, and may lay trophic or reproductive haploid eggs (Fresneau 1984, Oliveira and Hoelldobler 1991, Duessmann et al. 1996). Queenless colonies with reproductive intercastes may occur (Duessmann et al. 1996). Fighting amongst workers in establishing reproductive control has an energetic cost to the colony (Gobin et al. 2003).
Workers may exhibit tandem running, in which pairs of ants, one leading and one following, move toward a resource. Tandem running is mediated by a pheromone from the pygidial gland, which the lead ant rubs on its hind tibiae. The following ant maintains close contact with the lead ant, constantly antennating the hind legs of the lead ant (Hoelldobler and Traniello 1980, Traniello and Hoelldobler 1984).
In foraging, workers are able to use polarized light in orientation, and are able to judge distances (Duelli and Duelli-Klein 1976).
Workers may transport liquids between their mandibles, which they exchange with other workers (Hoelldobler 1985). Hoelldobler refers to this as an "external social bucket," which functions in the same capacity in social food exchange as the internal social crop of other ants. Carrying external liquid drops is considered a primitive condition relative to ants with a crop, and is exhibited by several other ponerines: Paraponera clavata, Ectatomma tuberculatum, Odontomachus sp., and Pachycondyla villosa.
I have twice observed verenae workers with lepidopteran larvae as prey. Once I observed a worker with a skipper larva (Hesperiidae). The second observation, at La Selva Biological Station, was more detailed:
I watched a Pachycondyla verenae worker attack and kill a lepidopteran larva. The larva was 1.7cm long and very fuzzy. The ant jumped on the back of the larva and the larva twitched violently, throwing the ant several cm away. This was repeated several times in rapid succession. Then the ant was able to hang on and kill the larva, because the larva suddenly went limp, and a pool of hemolymph appeared dorsally just behind the head. I saw both stinging and biting motions by the ant. The ant then tore at tufts of setae, and then began pulling the larva by the head.
Wild (2005) recently revised the apicalis complex. The abstract follows.
The taxonomy of the Neotropical Pachycondyla apicalis species complex is revised. Contrary tothe widely-held view that the apicalis complex contains only two species, P. apicalis (Latreille1802) and P. obscuricornis (Emery 1890), morphological evidence indicates the existence of threebroadly sympatric species. Examination of type specimens reveals that the name obscuricornis hasbeen extensively misapplied in the literature, and that the valid name for the widespread speciescommonly misdiagnosed as P. obscuricornis is P. verenae (Forel 1922). True P. obscuricornis isshown to be an uncommonly collected South American species. The name apicalis is valid as currentlyemployed for that species. A taxonomic key is provided, along with diagnoses, illustrations,and distributional data for all three species.
Duelli, P., R. Duelli-Klein 1976. Freilandversuche zum Heimfindevermoegen suedamerikanischer Ameisen (Formicidae: Ponerinae, Dolichoderinae, Formicinae) [Field studies on homing ability in South American ants]. Studia Entomologica 19:409-420.
Duessmann, O., C. Peeters, B. Hoelldobler 1996. Morphology and reproductive behaviour of intercastes in the ponerine ant Pachycondyla obscuricornis. Insectes Sociaux 43:421-425.
Emery, C. 1890. Voyage de M. E. Simon au Venezuela (Decembre 1887 - Avril 1888). Formicides. Annales de la Societe Entomologique de France (6) 10:55-76.
Fresneau, D. 1984. Developement ovarien et status sociale chez une fourmi primitive Neoponera obscuricornis Emery (Hym. Formicidae, Ponerinae). Insectes Soc. 31:387-402.
Gobin, B., J. Heinze, M. Strätz, and F. Roces. 2003. The energetic cost of reproductive conflicts in the ant Pachycondyla obscuricornis. Journal of Insect Physiology 49:747-752.
Hoelldobler, B. 1985. Liquid food transmission and antennation signals in ponerine ants. Israel Journal of Entomology 19:89-100.
Hoelldobler, B., J. Traniello 1980. Tandem running pheromone in ponerine ants. Naturwissenshchaften 67:360.
Oliveira, P. S., B. Hoelldobler 1991. Agonistic interactions and reproductive dominance in Pachycondyla obscuricornis (Hymenoptera, Formicidae). Psyche 98:215-226.
Traniello, J. F. A., B. Hoelldobler 1984. Chemical communication during tandem running in Pachycondyla obscuricornis (Hymenoptera, Formicidae). Journal of Chemical Ecology 10:783-794.
Wild, A. L. 2005. Taxonomic revision of the Pachycondyla apicalis species complex (Hymenoptera: Formicidae). Zootaxa 834:1-25.
Taxonomic Treatment (provided by Plazi)
Wild, A. L., 2005:
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(Figs. 5, 6, 9)
Neoponera apicalis var. verenae Forel 1922: 90.
Pachycondyla apicalis ; Emery 1890: 58-59. Not Latreille (1802). Misidentification.
Neoponera apicalis ; Wheeler and Wheeler 1952. Not Latreille (1802). Misidentification, description of larva.
Neoponera obscuricornis ; Brown 1957: 230; Kempf 1972: 162 (part). Not Emery (1890). Misidentification.
Pachycondyla obscuricornis ; Duelli and Duelli-Klein 1976: 411. Not Emery (1890). Misidentification; first explicit combination of the name obscuricornis in Pachycondyla .
Pachycondyla obscuricornis ; Hölldobler 1986: 89-99; Hölldobler and Wilson (1990): 266, 273, 280, 281, 292; Traniello and Hölldobler 1991: 783-794; Oliveira and Hölldobler 1991: 215; Lommelen et al 2002: 61-68; Wild 2003: 12; Longino 2004. Not Emery (1890). Misidentification.
Pachycondyla verenae (Forel 1922); Brown, in Bolton 1995: 311. (listed incorrectly as j. syn. of P. apicalis ; synonymy by Brown ). First explicit combination in Pachycondyla , the first implicit combination was by Brown (1973).
Other material examined:
Bolivia . Santa Cruz : 10k NWTerevinto [ PSWC ] ; 35k SSEFlor de Oro [ PSWC ] ; Las Gamas, P. N. Noel Kempf Mercado [ PSWC ] . Brazil . Amazonas : Faz. Esteio, 80k NNE Manaus [ PSWC ] ; Igarape Maua, S of Manaus [ MCZC ] ; Km 34 Manaus to Itacoatiara Hwy [ MCZC ] . Bahia : CEPEC/CEPLEC, Rodovia Ilhéus /Itabuna [ ALWC ] . Goiás : Faz. Acerio Jatai [ MCZC ] ; Mun. Anápolis , Km. 46 on road to Goiana [ MCZC ] . Pará : Belém [ LACM ] ; Mosqueiro [ LACM ] ; Pirelli Plantation (Iraboca) nr. Belém [ MCZC ] . Rondônia : Rio Madeira, Madeira Mamore R. R. Co. Camp #39 [ MCZC ] ; Rio Madeira, Madeira Mamore R. R. Co. Camp #41 [ MCZC ] . São Paulo : Agudos [ MCZC ] ; Cachoeira das Emas (EEBP), Piraçununga [ MCZC ] ; Faz. Campininha, Est. Ecol. Mogi Guaçu [ PSWC ] ; Rio Claro [ ALWC ] . Colombia . Cauca : Isla Gorgona [ MCZC ] ; nr. Yanaconas [ MCZC ] . Chocó : 10 km SW S. Jose de Palmar, Rio Torito, Finca Los Guaduales [ MCZC ] . Magdalena : 2-3 K aboveMinca [ MCZC ] ; 2k ESEMinca [ PSWC ] ; 4k NSan Pedro [ PSWC ] . Meta : Transecto Sumapaz [ PSWC ] . Valle : km 98, old road Cali to Buenaventura [ MCZC ] . Costa Rica . Cartago : 8 km ESEMoravia [ LACM ] ; Turrialba [ LACM , MCZC ] . Heredia : La Selva Biol. Sta. [ LACM , PSWC ] ; Heredia(s. loc.) [ LACM ] . Limón : 10 km ESEMoravia [ LACM ] ; R. Toro Amarillo, vic. Guapiles [ MCZC ] ; Zent [ LACM , MCZC ] . Puntarenas : Corcovado Nat. Park, Llorona [ LACM , MCZC , PSWC ] ; Ojo de Agua [ LACM ] ; Res. Biol. Carara [ LACM , PSWC ] . Ecuador . Napo : Jatun Sacha 7k ESE Pto. Misahualli [ PSWC ] . Pichincha : 1 mi. WSanto Domingo de los Colorados [ MCZC ] ; ENDESA Forest Reserve [ ALWC ] . “Durena” (loc. indet.) [ LACM ] . French Guiana . Cayenne : 35 km WSinnamary [ LACM ] . Guyana . Cuyuni-Mazaruni: Bartica Dist. [ MCZC ] ; Camaria [ MCZC ] ; Cuyani R. [ MCZC ] ; Kamakusa [ MCZC ] . Demerara-Mahaica : Dunoon [ MCZC ] . Honduras . Atlántida : 14 km SLa Ceiba [ MCZC ] ; Lancetilla, nr. Tela [ MCZC ] . Colón : Sangrelaya [ LACM ] . Olancho : El Boqueron [ MCZC ] . Mexico . Guerrero : (s.loc.) [ MCZC ] . Veracruz : Laguna Encantada [ MCZC ] ; Las Hamacas, 17k N Santiago, nr. Tuxtla [ MCZC ] ; Presidio, Trail above Presidio [ LACM ] ; Pueblo Nuevo nr. Tezonapa [ MCZC ] . Nicaragua . Granada : Granada [ LACM ] . Rivas : Pica Pica [ LACM ] . Atlántico Sur : Masilena nr. Bluefields [ MCZC ] . Paraguay . Amambay : Parque Nacional Cerro Corá [ ALWC , INBP ] . Caaguazú : Pastoreo [ MZSP ] . Canindeyú : Col. 11 de Setiembre [ ALWC ] ; Res. Nat. Bosque Mbaracayú , Lagunita [ ALWC , MCZC ] ; Res. Nat. Bosque Mbaracayú , Aguara Ñu [ ALWC ] . Misiones : Ayolas [ INBP ] . Paraguarí : Parque Nacional Ybycuí [ ALWC ] . Panama . Chiriquí : Bugaba [ MCZC ] . Coclé : El Copé [ LACM ] . Colón : Gamboa, C. Z. [ LACM ] . Panamá : Barro Colorado I. [ LACM , MCZC , UCDC ] . Peru . Junin : (s. loc.) [ MCZC ] . Huánuco : 43 mi. ETingo Maria [ MCZC ] ; 5 mi. S.Las Palmas [ LACM ] . Madre de Dios : 15 k NEPuerto Maldonado [ MCZC ] ; Est. Biol. Cocha Cashu [ LACM ] ; Rio Tambopata, 10 km S Puerto Maldonado [ LACM ] . Venezuela . Bolívar : 49k ENETumeremo [ PSWC ] ; Río Grande, Imataca For. Res. [ PSWC ] ; Guárico P. N. Guatapo Hae. Elvira [ MCZC ] .
Worker measurements: (n = 23) HL 2.16-2.51, HW 1.60-1.87, SL 2.36-2.77, WL 3.41-4.05, FL 2.26-2.66, LHT 2.63-3.17, PL 0.87-1.13, PH 1.12-1.33, CI 0.70-.79, SI 1.32-1.59.
Worker diagnosis: A smaller species (WL <4.1 mm) with a long antennal scape and a short, posterolaterally emarginate petiole. Head narrow (CI <.79); mandibles elongatetriangular and bearing 12-14 teeth. Antennal scape longer than head length. Posterior and lateral faces of propodeum distinct and meeting at a sharp angle which is sometimes produced into a small ridge. Posterior and lateral faces of petiole distinct, meeting at a relatively sharp margination. Petiolar node relatively short (PH <1.35 mm). Abdominal tergite 3 lacking erect setae, tergite 4 occasionally with 1-2 erect setae along posterior margin. Hypopygium coarsely punctate posteriorly, with shining interspaces in area adjacent to sting, bearing moderate to sparse subdecumbent pubescence that does not completely obscure integument (as in Fig. 7). Body and appendages dark brown to black; apical antennomeres and tarsomeres medium reddish-brown to dark brown.
This species may be separated from P. apicalis and P. obscuricornis by the marginate form of the petiole.
Geographic variation: Specimens from the southern parts of the range have shorter antennal scapes (SL <2.5mm) and broader heads (CI>.76), although they never approach the condition of P. obscuricornis . Additionally, specimens from Paraguay and southern Brazil show a less marked development of the posterolateral emargination of the petiolar node than specimens from elsewhere in the range.
Distribution: Southern Mexico to Paraguay.
Biology: Almost all the information published about P. verenae appears in the literature under the name P. obscuricornis (see Discussion).
This common species exhibits great flexibility in habitat. 14 specimen records are from rainforest or other types of wet forest, seven are from forest edge habitats, five from open natural habitats such as campo cerrado or savannah, one from pasture, one from tropical scrub forest, and one from a cacao plantation. Interestingly, southern populations seem to be more commonly collected in open habitats, while northern populations are more likely to be found in forest. This species displays similar nesting habits to P. apicalis and P. obscuricornis . Three nest records from specimen collection data were from rotting wood, and one from a grass clump in a pasture. Traniello and Hölldobler ’s (1984) study colony was collected nesting in a log in Panama, and Wild (2003) reports a nest in rotting wood in Paraguay.
Pachycondyla verenae is a predaceous and scavenging species. Foragers will also carry droplets of liquid held between their mandibles, a common trait in poneromorph ants ( Hölldobler 1986). Longino (2004) has observed P. verenae attacking live lepidopteran larvae in Costa Rica, and captive colonies have taken crickets, cockroaches, termites, and other insect parts (Traniello & Hölldobler 1984, Oliveira & Hölldobler 1991, Gobin et al 2003). Foragers use visual cues (Duelli & Duelli-Klein 1976), and there is no recruitment to food sources (Traniello & Hölldobler 1984).
Colonies are small, reportedly with fewer than 100 workers. Gobin et al (2003) collected 27 colonies from La Selva in Costa Rica with a median number of 39 workers per colony. The study colony of Fresneau (1984) contained 57 workers, and that of Traniello and Hölldobler (1984) grew to about 80-90 workers. P. verenae appears to be polygynous. Traniello and Hölldobler ’s study colony had “several” fertile queens, and Fresneau (1984) found developed ovaries in five of seven dealate queens. Oliveira & Hölldobler (1991) described the agonistic interactions between workers and unmated queens in a queenless laboratory colony. These dominance interactions have a measurable energetic cost to the colony (Gobin et al 2003).
Pachycondyla verenae has been the subject of considerable research on gland structure. Abdominal glands in the male were described by Hölldobler and Engel-Siegel (1982), the pygidial gland by Traniello and Hölldobler (1984), the metapleural gland was briefly investigated by Hölldobler and Engel-Siegel (1985), and the ultrastructure of the labial gland was reported by Lommelen et al (2002, 2003).
Tandem-running, a stereotyped behavior where an ant recruits a single nestmate at a time, was investigated in P. verenae by Traniello and Hölldobler (1984). P. verenae was found to employ tandem-running during nest relocation, mediated by a pheromone originating in the pygidial gland of the lead ant and spread to the hind-legs by a self-grooming behavior.
There is one record in MCZC of P. verenae in the gut contents of Bufo coniferus Cope in Nicaragua.
Wild, A. L., 2007:
Amambay, Caaguazú , Canindeyú , Misiones, Paraguarí (ALWC, INBP, LACM, MCZC, MZSP). Literature records: Amambay, Caaguazú , Canindeyú , Misiones, Paraguarí (Wild 2005).