Solenopsis picea

Solenopsis picea nests under stones in dark clay loam soils. Brood and sexuals were collected in nests in Mexico in May. Solenopsis picea was also collected from a nest in the extremities of dried Psidium pomiferum in Brazil (Forel 1903). This species was collected in the thin partitions separating the chambers of ant gardens inhabited by Crematogaster carinata and Camponotus femoratus in British Guiana (Weber 1943). Habitats include transitional bamboo/cloud forest, hardwood, montane cloud forest, wet montane forest, wet cloud forest, old growth tropical forest, oak ridge and coffee plantations. (Pacheco and Mackay 2013)

Identification
A New World thief ant that is a member of the molesta species complex. (Key to New World Solenopsis Species Complexes)

Pacheco and Mackay (2013) – Worker - This is a black/dark brown (occasionally light brown or somewhat bicolored with the gaster darker than the remainder of the ant), medium sized species (total length 1.56 mm). The head is nearly quadrate, with fine cephalic punctures and short (0.030 mm) hairs. The lateral clypeal teeth are well developed. It has small eyes with 3-5 ommatidia. There are horizontal striae on the mesopleuron and metapleuron. The petiole is noticeable longer than the postpetiole when viewed laterally. Queen - The queen is concolorous brown. The lateral teeth are well developed and extend about 0.030 mm beyond the anterior clypeal border. The scape is thick, 0.090 mm in diameter. Thin vertical striae are present on the frontal lobes. The scape, head and pronotum are covered in coarse punctures. Thin horizontal striae are present on the lower half of the metapleuron and just anterior to the propodeal spiracle. There are teeth present on the bottom of both the petiolar peduncle and postpetiole, however the petiolar peduncle's tooth is better developed than the one present on the postpetiole (which is more like an angle). Male - The male is very dark brown (almost black). The legs and antennae are lighter brown in color. The clypeus is slightly concave with no presence of a tooth, bump or angle on the margin. Tiny striae is present on the clypeus and follow the clypeal margin. Thin vertical striae are present on the head from the ocelli to the frontal lobes. Punctures are present on the first segment of the antennae. No punctures are visible on the head, pronotum or rest of the mesosoma.

Workers are easily confused with those of Solenopsis castor. Solenopis picea are not as dark mahogany brown as is S. castor and the minor segments of the antennae are longer, nearly always greater in length than 0.100 mm (nearly always less than 0.120 mm in S. castor). If queens are available, these two species are easily separated, as the queens of S. picea are large (total length> 4 mm), compared to the much smaller queens of S. castor (TL up to 3 mm). The male of S. picea is similar to a male of Solenopsis pollux, but can be distinguished as S. pollux is slightly larger and has golden yellow antennae as opposed to the brown coloration of S. picea (=S. nigelloides). Additionally, S. picea (= S. nigelloides) lacks coarse punctures on the head and pronotum.

Distribution
Mexico south to Argentina, Brazil, Guiana; Caribbean Region (Cuba, Puerto Rico).

Distribution based on Regional Taxon Lists
Neotropical Region: Argentina, Belize, Bolivia, Brazil , Colombia, Costa Rica , Cuba, Greater Antilles, Guatemala, Guyana , Honduras, Mexico, Panama, Peru, Puerto Rico.

Biology
Philpot et al. (2018) reported this species was one of the most common ants in an experimental study examining colonization of twigs in shade-coffee forests in Chiapas, Mexico (17.7% of the 202 nests found in 796 recovered twigs).

It has been found nesting in the thin partitions separating nest chambers within the ant gardens inhabited by and  (Weber, 1943) in British Guiana.

Nomenclature

 *  picea. Solenopsis picea Emery, 1896g: 89 (w.q.) COSTA RICA. Wheeler, G.C. & Wheeler, J. 1955c: 135 (l.). Subspecies of tenuis: Forel, 1912g: 8. Revived status as species: Mann, 1922: 30. Senior synonym of nigelloides, parabiotica, reducta, subadpressa: Pacheco & Mackay, 2013: 263.
 * nigelloides. Solenopsis angulata r. nigelloides Forel, 1913l: 223 (w.q.m.) ARGENTINA. Junior synonym of picea: Pacheco & Mackay, 2013: 263.
 * parabiotica. Solenopsis parabiotica Weber, 1943a: 90, fig. 2 (w.q.) GUYANA. Junior synonym of picea: Pacheco & Mackay, 2013: 263.
 * reducta. Solenopsis picea subsp. reducta Menozzi, 1927c: 276 (w.) COSTA RICA. Junior synonym of picea: Pacheco & Mackay, 2013: 263.
 * subadpressa. Solenopsis picea r. subadpressa Forel, 1903c: 257 (w.) BRAZIL. [Also described as new by Forel, 1908e: 66.] Junior synonym of picea: Pacheco & Mackay, 2013: 263.

Worker
Pacheco and Mackay (2013) - Measurements (n=14). TL 1.38-2.04 (1.56); HL 0.402-0.540 (0.481); HW 0.336-0.510 (0.411); EL 0.042-0.060 (0.049); ED 0.030-0.042 (0.035); SL 0.282-0.396 (0.336); FSL 0.120-0.180 (0.137); CI 80.0-94.4 (85.4); SI 61.2-79.3 (69.9); PL 0.072-0.108 (0.087); PW 0.090-0.162 (0.125); PI 55.6-82.4 (70.3); PPL 0.102-0.132 (0.109); PPW 0.108-0.180 (0.149); PPI 65.5-94.4 (74.7); WL 0.300-0.450 (0.367); PSL 0.024-0.060 (0.037); PSW 0.024-0.060 (0.036).

Dark brown to light brown, sometimes with gaster lighter in color than body; head square-shaped, cephalic punctures fine; lateral clypeal teeth well developed; extralateral teeth angular to absent; eyes small, black, with 3-5 ommatidia; minor funicular segments 3-8 slender, long (0.137 mm); notopropodeal suture well depressed; horizontal striae on mesopleuron and metapleuron; petiole noticeable longer than postpetiole viewed laterally.

Moderately hairy, with erect and sub erect hairs on all body surfaces; cephalic punctures fine and hairs very short (0.030 mm); hairs on scape short; suberect hairs of petiole and postpetiole curved posteriorly.

Queen
Pacheco and Mackay (2013) - Measurements (n=2). TL 3.96-4.68 (4.32); HL 0.666-0.720 (0.693); HW 0.588-0.660 (0.624); EL 0.186-0.258 (0.222); ED 0.144-0.204 (0.174); MOL 0.048-0.072 (0.060); MOD 0.054-0.060 (0.057); SL 0.456-0.480 (0.468); FSL 0.204-0.282 (0.243); CI 88.3-91.7 (89.9); SI 66.7-68.5 (67.6); PSL 0.048-0.066 (0.057); PSW 0.060-0.072 (0.066); PL 0.144-0.150 (0.147); PW 0.240-0.324 (0.282); PI 44.4-62.5 (53.5); PPL 0.240; PPW 0.264-0.438 (0.351); PPI 54.8-90.9 (72.9); WL 0.900-0.960 (0.930).

Concolorous brown; head quadrate; lateral clypeal teeth well developed, extend 0.030 mm beyond anterior clypeal border; clypeal carinae well developed, extend posterior to antennal insertions; extralateral teeth smaller in size, angular; scape thick, 0.090 mm in diameter; thin vertical striae on frontal lobes; scape, head, pronotum with coarse punctures; eyes small; thin horizontal striae on entire side of propodeum; petiole and postpetiole horizontally striate, subpeduncular tooth well developed, tooth ventrally on postpetiole angular.

Abundantly hairy, hairs present on all body surfaces; nearly every puncture on body has suberect hair.

Male
Pacheco and Mackay (2013) - Measurements (n=1). TL 3.48; HL 0.600; HW 0.642; EL 0.270; ED 0.180; MOL 0.054; MOD 0.078; SL 0.222; FSL 1.68; CI 107.0; SI 37.0; PSL 0.060; PSW 0.066; PL 0.150; PW 0.264; PI 56.8; PPL 0.180; PPW 0.330; PPI 54.5; WL 0.840.

Dark brown, legs and antennae lighter brown; clypeus slightly concave, with no presence of tooth, bump or angle on anterior margin; vertical striae follow clypeal margin; thin vertical striae extend from ocelli to frontal lobes; three ocelli clear, eyes black; scape with coarse punctures; no punctures visible on head, pronotum or remainder of mesosoma; side of propodeum entirely striated; sparse striae present basally on petiole and postpetiole; no visible tooth, angle or bump on subpeduncular process or subpostpetiolar process.

Abundantly hairy, with hair present on all body surfaces, most hairs are suberect and curve posteriorly.

Type Material
Solenopsis angulata nigelloides, Museo Civ. Genova, Forel Coll., Argentina, Buenos Aires x. 1912, G. Roverto (lectotype worker, 5 paralectotype workers, 1 paralectotype queen and 1 paralectotype male [here designated], ). Solenopsis picea subadpressa Brazil, Ceara, Dr. Rocha (lectotype worker M.C.Z. cotype 1, 22616, ). Solenopsis angulata carettei ardua Sammlung, Dr. F. Santschi, Kairouan Argentina, Parana, Rio Negro, Reichensperger, 1928 (2 workers, 1 queen NHMB). Solenopsis parabiotica, types not found, specimens apparently identified by Weber found in MCZC (10 workers).

References based on Global Ant Biodiversity Informatics

 * Achury R., and A.V. Suarez. 2017. Richness and composition of ground-dwelling ants in tropical rainforest and surrounding landscapes in the Colombian Inter-Andean valley. Neotropical Entomology https://doi.org/10.1007/s13744-017-0565-4
 * Adams B. J., S. A. Schnitzer, and S. P. Yanoviak. 2016. Trees as islands: canopy ant species richness increases with the size of liana-free trees in a Neotropical forest. Ecography doi: 10.1111/ecog.02608
 * Adams B. J., S. A. Schnitzer, and S. P. Yanoviak. 2019. Connectivity explains local ant community structure in a Neotropical forest canopy: a large-scale experimental approach. Ecology 100(6): e02673.
 * Adams, R.M.M. and J.T. Longino. 2007. Nesting biology of the arboreal fungus-growing ant Cyphomyrmex cornutus and behavioral interactions with the social-parasitic ant Megalomyrmex mondabora. Insectes Sociaux 54:136-143
 * Aguayo C. G. 1932. Notes on West Indian ants. Bulletin of the Brooklyn Entomological Society 27: 215-227.
 * Brandao, C.R.F. 1991. Adendos ao catalogo abreviado das formigas da regiao neotropical (Hymenoptera: Formicidae). Rev. Bras. Entomol. 35: 319-412.
 * Culver D. C. 1974. Species packing in Caribbean and North Temperate ant communities. Ecology 55(5): 974-988.
 * Dattilo W. et al. 2019. MEXICO ANTS: incidence and abundance along the Nearctic-Neotropical interface. Ecology https://doi.org/10.1002/ecy.2944
 * Davidson, D.W. 2005. Ecological stoichiometry of ants in a New World rain forest. Oecologia 142:221-231
 * De la Mora, A., C. J. Murnen, and S. M. Philpott. 2013. Local and landscape drivers of biodiversity of four groups of ants in Neotropical coffee landscapes. Biodiversity and Conservation 22: 871-888.
 * Emery C. 1896. Studi sulle formiche della fauna neotropica. XVII-XXV. Bullettino della Società Entomologica Italiana 28: 33-107.
 * Ettershank G. 1966. A generic revision of the world Myrmicinae related to Solenopsis and Pheidologeton (Hymenoptera: Formicidae). Aust. J. Zool. 14: 73-171.
 * Fernandes, P.R. XXXX. Los hormigas del suelo en Mexico: Diversidad, distribucion e importancia (Hymenoptera: Formicidae).
 * Fernández, F. and S. Sendoya. 2004. Lista de las hormigas neotropicales. Biota Colombiana Volume 5, Number 1.
 * Fontanla Rizo J.L. 1997. Lista preliminar de las hormigas de Cuba. Cocuyo 6: 18-21.
 * Fontenla J. L., and J. Alfonso-Simonetti. 2018. Classification of Cuban ants (Hymenoptera: Formicidae) into functional groups. Poeyana Revista Cubana de Zoologia 506: 21-30.
 * Fontenla Rizo J. L. 1997. Lista preliminar de las hormigas de Cuba (Hymenoptera: Formicidae). Cocuyo 6: 18-21.
 * Forel A. 1903. Mélanges entomologiques, biologiques et autres. Ann. Soc. Entomol. Belg. 47: 249-268.
 * Forel A. 1908. Catálogo systemático da collecção de formigas do Ceará. Boletim do Museu Rocha 1(1): 62-69.
 * Gonthier, D. J., K. K. Ennis, S. M. Philpott, J. Vandermeer, and I. Perfecto. 2013. Ants defend coffee from berry borer colonization. BioControl 58: 815-820.
 * Gove, A. D., J. D. Majer, and V. Rico-Gray. 2009. Ant assemblages in isolated trees are more sensitive to species loss and replacement than their woodland counterparts. Basic and Applied Ecology 10: 187-195.
 * Jeanne R. J. 1979. A latitudinal gradient in rates of ant predation. Ecology 60(6): 1211-1224.
 * Kempf, W.W. 1972. Catalago abreviado das formigas da regiao Neotropical (Hym. Formicidae) Studia Entomologica 15(1-4).
 * Koptur, S., M. Palacios-Rios, C. Diaz-Castelazo, W. P. Mackay, and V. Rico-Gray. 2013. Nectar secretion on fern fronds associated with lower levels of herbivore damage: field experiments with a widespread epiphyte of Mexican cloud forest remnants. Annals of Botany 111: 1277-1283.
 * Kusnezov N. 1953. La fauna mirmecológica de Bolivia. Folia Universitaria. Cochabamba 6: 211-229.
 * Larsen, A., and S. M. Philpott. 2010. Twig-nesting ants: the hidden predators of the coffee berry borer in Chiapas, Mexico. Biotropica 42: 342-347.
 * Longino J. T. 2013. Ants of Nicargua. Consulted on 18 Jan 2013. https://sites.google.com/site/longinollama/reports/ants-of-nicaragua
 * Longino J. T., and R. K. Colwell. 2011. Density compensation, species composition, and richness of ants on a neotropical elevational gradient. Ecosphere 2(3): 16pp.
 * Longino J. et al. ADMAC project. Accessed on March 24th 2017 at https://sites.google.com/site/admacsite/
 * Maes, J.-M. and W.P. MacKay. 1993. Catalogo de las hormigas (Hymenoptera: Formicidae) de Nicaragua. Revista Nicaraguense de Entomologia 23.
 * Mann W. M. 1916. The Stanford Expedition to Brazil, 1911, John C. Branner, Director. The ants of Brazil. Bulletin of the Museum of Comparative Zoology 60: 399-490
 * Mann W. M. 1922. Ants from Honduras and Guatemala. Proceedings of the United States National Museum 61: 1-54.
 * Menozzi C. 1927. Formiche raccolte dal Sig. H. Schmidt nei dintorni di San José di Costa Rica. Entomologische Mitteilungen. Berlin-Dahlem. 16: 266-277.
 * Menozzi C. 1931. Contribuzione alla conoscenza del microgenton di Costa Rica. III. Hymenoptera - Formicidae. Bollettino del Laboratorio di Zoologia Generale e Agraria della Reale Scuola Superiore d'Agricoltura. Portici. 25: 259-274.
 * Morris, J. R., and I. Perfecto. 2016. Testing the potential for ant predation of immature coffee berry borer (Hypothenemus hampei) life stages. Agriculture, Ecosystems & Environment 233: 224-228.
 * Pacheco J. A., and W. P. Mackay. 2013. The systematics and biology of the New World thief ants of the genus Solenopsis (Hymenoptera: Formicidae). Lewiston, New York: Edwin Mellen Press, 501 pp.
 * Smith M. R. 1937. The ants of Puerto Rico. Journal of Agriculture of the University of Puerto Rico 20: 819-875.
 * Vásquez-Bolaños M. 2011. Lista de especies de hormigas (Hymenoptera: Formicidae) para México. Dugesiana 18: 95-133
 * Weber N. A. 1943. The queen of a British Guiana Eciton and a new ant garden Solenopsis (Hymenoptera: Formicidae). Proc. Entomol. Soc. Wash. 45: 88-91.
 * Wheeler W. M. 1908. The ants of Porto Rico and the Virgin Islands. Bulletin of the American Museum of Natural History 24: 117-158.
 * Wheeler W. M. 1914. Ants collected by W. M. Mann in the state of Hidalgo, Mexico. Journal of the New York Entomological Society 22: 37-61.
 * Wheeler W. M. 1925. Neotropical ants in the collections of the Royal Museum of Stockholm. Arkiv för Zoologi 17A(8): 1-55.
 * Wheeler W. M. 1942. Studies of Neotropical ant-plants and their ants. Bulletin of the Museum of Comparative Zoology 90: 1-262.
 * Wilson, E.O. 1987. The Arboreal Ant Fauna of Peruvian Amazon Forests: A First Assessment. Biotropica 19(3):245-251.