Pachycondyla striata

Pachycondyla striata nests in rotten wood, under logs, or in the soil and forages on the soil surface (Mackay and Mackay).

Identification
From Mackay and Mackay (2010): There are several species of New World Pachycondyla in which the workers and females have conspicuous striae on the dorsum of the head, including Pachycondyla tarsata, Pachycondyla fuscoatra, Pachycondyla lineaticeps, Pachycondyla magnifica and P. striata. Pachycondyla striata can be easily separated from P. tarsata, as it lacks the inner claw on the tarsal claws and the swellings on the upper anterior region of the postpetiole, both of which are present in P. tarsata. Pachycondyla striata differs from P. lineaticeps in the shape of the petiole, which is nearly rectangular, not with the posterior face broadly rounded into the dorsal face. Additionally P. striata is much larger (total length of P. lineaticeps 10 mm). Pachycondyla striata can also be separated as it occurs mostly in southern South America, not Central America and northern South America as does P. lineaticeps. The striae on the head and dorsum of the pronotum of P. striata are not as coarse and well defined as they are in P. magnifica. Pachycondyla striata has approximately 50 striae across the widest point of the pronotum, whereas P. magnifica has about 35. Pachycondyla striata could be easily confused with P. fuscoatra. It differs in having a well-developed pronotal carina (lacking in P. fuscoatra) and the stria on the head are finer and not as well defined. Pachycondyla striata can be confused with Pachycondyla impressa, but differs in that P. impressa lacks the striae on the head and lacks a well-developed carina on the pronotal shoulder. Otherwise they are very similar.

The males of three common species are very similar: P. striata, P. impressa and Pachycondyla villosa. Pachycondyla striata can be separated from the other two by the presence of dense erect hairs on most of the surfaces (sparse or only moderately abundant in the other two species). The subpetiolar process of P. striata is angulate anteriorly, not broadly rounded as in P. impressa, or with a large ventral process in P. villosa.

Distribution
BRASIL, BOLIVIA, PARAGUAY, ARGENTINA, URUGUAY (Mackay and Mackay 2010)

This taxon was described from Brazil.

Habitat
Pachycondyla striata can be found in wet myrtaceous forest, rain forest, riparian rain forest, open grassy areas and cerrado [scrub vegetation], at sea level to 1300 meters elevation. (Mackay and Mackay 2010)

Nomenclature

 *  striata. Pachycondyla striata Smith, F. 1858b: 106 (w.) BRAZIL. Roger, 1861a: 6 (q.); Santschi, 1921g: 86 (m.); Wheeler, G.C. & Wheeler, J. 1952c: 616 (l.). Senior synonym of nitidiventris: Kempf, 1961c: 210. See also: Mackay & Mackay, 2010: 527.
 * nitidiventris. Pachycondyla striata var. nitidiventris Santschi, 1921g: 87 (w.) URUGUAY. Junior synonym of striata: Kempf, 1961c: 201.

Worker
From Mackay and Mackay (2010): The worker is a relatively large (total length about 13 mm) dark brown specimen with lighter brown appendages. The mandibles have about 12 teeth. The anterior medial border of the clypeus is slightly concave, the eyes are moderately large (0.58 mm maximum diameter) located approximately one diameter from the anterior edge of the head (side view). The malar carina is absent. The scape extends past the posterior lateral corner of the head. The posterior margin of the head is concave. The pronotal carina is well developed and sharp and slightly overhangs the side of the pronotum (similar to that of Pachycondyla villosa). The metanotal suture is not marked on the dorsum of the mesosoma. The dorsal face of the propodeum slopes broadly into the posterior face, the propodeal spiracle is slit-shaped. The petiole is thick when viewed in profile and rectangular-shaped. The anterior face of the postpetiole is vertical and sharply bends into the dorsal face, nearly forming an angle. The dorsal face of the pygidium is concave, as in Pachycondyla impressa.

Erect hairs are present on most surfaces, including the clypeus, dorsal and ventral surfaces of the head, sides of the head, scapes, dorsum of the mesosoma, legs, including the tibiae, dorsal surface of the petiole and all surfaces of the gaster; appressed golden pubescence is sparse on most surfaces except the gaster, where it is moderately dense.

The dorsum of the head is mostly finely striate longitudinally; the striae are poorly developed on the sides of the head, but striae are present on the side of the mesosoma as well as the dorsum. The side of the petiole is nearly without striae; the dorsum of the petiole has mostly transverse very fine striae. The gaster is mostly punctate.

Queen
From Mackay and Mackay (2010): The female is similar to the worker in lacking the malar carina, having relatively large eyes, a well-developed carina on the pronotal shoulder and a similar shaped petiole. It is a large (total length 15 mm) black specimen with brown legs.

Erect and suberect golden hairs are abundant on the mandibles, clypeus, dorsal and ventral surfaces of the head, posterior margin, sides of the head, dorsum of the mesosoma, dorsum of the petiole, subpetiolar process and all surfaces of the gaster. The hairs on the legs are similar and abundant but are mostly suberect. Appressed golden pubescence is dense on most surfaces, but is fine and hides little of the surface sculpturing.

The striae are also present on the dorsum of the head but are poorly developed, especially on the sides of the head. The mandibles are mostly covered with fine striae. The dorsum of the pronotum has numerous mostly longitudinal striae, the scutum and scutellum are covered with coarse longitudinal striae. The mesopleuron and metapleuron are covered with fine nearly horizontal striae; the remainder of the ant is dull and punctate.

Male
From Mackay and Mackay (2010): The male is a large (total length 13 mm) dark brown specimen. The anterior edge of the clypeus is convex to slightly concave and the clypeus is swollen in the middle. The eyes are large and occupy approximately one half of the side of the head. The ocelli are small (maximum diameter of the median ocellus 0.12 mm), the median ocellus is located 0.2 mm from the lateral ocellus, which is greater than the diameter as the median ocellus.

The pronotal shoulder is swollen and forms a raised area, which is broadly rounded. The propodeal spiracle is slit-shaped. The petiole is thick when viewed in profile with the two faces converging dorsally and forming a rounded apex. The subpetiolar process is angulate anteriorly and gradually diminishes posteriorly. Coarse erect hairs are extremely abundant on all surfaces, especially the head, the mesosoma and petiole. Fine appressed golden pubescence is also abundant on most surfaces.

The head of the male is punctate or coriaceous, as is the mesosoma and the petiole, the gaster is finely punctate, most surfaces are dull, the mesosoma is weakly shining, as is the petiole, the gaster slightly more shining.

Type Material
2 syntype workers seen, ; 4 cotypes seen,. (Mackay and Mackay 2010)

Type Locality Information
Brasil, Rio de Janeiro; Uruguay, Nueva Helvetia; Brasil, Mato Grosso, frontier with Bolivia. (Mackay and Mackay 2010)

Etymology
The name of this species is derived from the Latin word stria, meaning channel or furrow, referring to the striae on numerous parts of the body, especially the pronotum. (Mackay and Mackay 2010)

Additional References

 * da Silva-Melo, A. & Giannotti, E. 2010. Nest architecture of Pachycondyla striata Fr. Smith, 1858 (Formicidae, Ponerinae). Insectes Sociaux 57, 17–22 (DOI 10.1007/s00040-009-0043-z).
 * da Silva-Melo, A. & Giannotti, E. 2011. Life Expectancy and Entropy Values for Workers of Pachycondyla striata (Hymenoptera: Formicidae: Ponerinae). Sociobiology, 58, 143-150.
 * da Silva-Melo, A. & Giannotti, E. 2012. Division of Labor in Pachycondyla striata Fr. Smith, 1858 (Hymenoptera: Formicidae: Ponerinae). Psyche Volume 2012, Article ID 153862, 7 pages (doi:10.1155/2012/153862). PDF
 * Eidmann, H. 1936. Ökologisch-faunistische Studien an südbrasilianischen Ameisen. Arbeiten über physiologische und angewandte Entomologie aus Berlin-Dahlem 3:26-48, 81-114, + 1 plate, 5 text figures.
 * Emery, C. 1894a. Die Ameisen von Rio Grande do Sul von Dr. H. von Jhering. Berliner Entomologische Zeitschrift 39:321-446.
 * Forster-Figueira, C. and M. Camargo Mathias. 2002. Histological, histochemical and Morphometric Studi of female corpora allata of Pachycondyla striata ants (Hymenoptera: Ponerinae). Sociobiology 39:77-87.
 * Morgan, E., R. do Nascimento, S. Keegans and J. Billen. 1999. Comparative study of mandibular gland secretions of workers of ponerine ants. Journal of Chemical Ecology 25:1395-1409.
 * Morgan, E., H. Jungnickel, S. Keegans, R. do Nascimento, J. Billen, B. Gobin and F. Ito. 2003. Comparative survey of abdominal gland secretions of the ant subfamily Ponerinae. Journal of Chemical Ecology 29:95-114.
 * Ortiz, G. and M. I. Camargo-Mathias. 2003. Morphological study of the venom gland in workers of the ant Pachycondyla striata F. Smith (Hymenoptera: Formicidae). Socio-biology 42:103-116.
 * Passos, L. and S. Ferreira. 1996. Ant dispersal of Croton priscus (Euphorbiaceae) seeds in a tropical semideciduous forest in south-eastern Brazil. Biotropica 28:697-700.
 * Passos, L. and P. Oliveira. 2002. Ants affect the distribution and performance of seedlings of Clusia criuva, a primarily bird-dispersed rain forest tree. Journal of Ecology 90:517-528.
 * Pizo, M. and P. Oliveira. 2000. The use of fruits and seeds by ants in the Atlantic forest of southeast Brazil. Biotropica 32:81-861.
 * Reichensperger, A. 1936. Beltrag zur Kenntnis der Myrmecophilen und Termitophilenfauna Brasiliens und Costa Ricas. IV. (Col. Hist. Staphyl. Pselaph.). Revista de Entomologia 6:222-242.
 * MS Rodrigues, EF Vilela, DO Azevedo & RR Hora. 2011. Multiple Queens in Founding Colonies of the Neotropical Ant Pachycondyla striata Smith (Formicidae: Ponerinae). Neotropical Entomology, 40, 293-299.
 * Tomotake, M.E., M. Mathias, A. Yabuki and F. Caetano. 1992 Scanning electron microscopy of mandibular glands of workers and queens of the ants Pachycondyla striata, (Hymenoptera: Ponerinae). Journal of Advanced Zoology 13:1-6.
 * Tomotake, M.E., M. Mathias, A. Yabuki and F. Caetano. 1992 Scanning electron microscopy of mandibular glands of workers and queens of the ants Pachycondyla striata, (Hymenoptera: Ponerinae). Journal of Advanced Zoology 13:1-6.