Amoimyrmex striatus

Barrera et al. (2015) studied the diversity of leaf cutting ants along a forest-edge-agriculture habitat gradient. Their study site, in Chaco Serrano of Central Argentina, had forest remnants of various sizes within an agriculture area with wheat, soy and maize. A. striatus was the moderately abundant (17% of the 162 Acromyrmex colonies sampled). Along the forest edge it was similar in abundance to Acromyrmex lundii, with Acromyrmex crassispinus also present but occurring at a slightly lower abundance. A few colonies of Acromyrmex heyeri and Acromyrmex silvestrii were also found along the forest edge. Ten Acromyrmex nets were found within 5m of the forest edge but none were sampled 25m from the forest edge in the croplands. A. striatus was not found in the forest interior but was the most common species in the cropland matrix close to the forest edge. This suggests this species may do well in disturbed areas. In some regions A. striatus is known as a pest species (Diehl-Fleig, 1993).

Distribution based on Regional Taxon Lists
Neotropical Region: Argentina, Bolivia, Brazil, Paraguay, Uruguay.

Biology
Jofre et al. (2018) - Amoimyrmex striatus is one of the most common leaf-cutting ant species in Argentina (Farji-Brener & Ruggiero, 1994). This species constructs relative small subterranean nests in areas of low vegetation cover. Workers forage at close distances from the nest without a defined network trail system (Boneto, 1959; Diehl-Fleig, 1995). Amoimyrmex striatus consumes a high percentage of species available in the environment (Armani & Quirán, 2007; Nobua-Behrmann, 2014), and their degree of selectivity or opportunism depends on the availability of resources within the proximity of their colonies (Farji-Brener & Protomastro, 1992; Pilati et al., 1997; Franzel & Farji-Brener, 2000; Armani & Quirán, 2007; Nobua-Behrmann, 2014).

Foraging
Nobua-Behrmann et al. (2017) studied temporal and thermal aspects of Amoimyrmex striatus foraging behavior in the Monte Desert in Argentina where this species co-occurs with Acromyrmex lobicornis. Amoimyrmex striatus colonies were active during spring and summer, with no signs of foraging activity during winter. Foraging intensity was highest during spring and summer, with up to 90 ants (foragers returning to the nest) / 5 minutes. During spring and summer, foraging activity was exclusively diurnal with 4 - 6 hours of foraging during the morning and 4 hours in the afternoon, avoiding the hotter midday. This changed to a single period of low activity concentrated during the hottest part of the day in autumn. During the hottest months, the overall daily foraging pattern appears to be complementary to its similar co-occurring congener: A. striatus daily foraging activity begins in the mornings when A. lobicornis colonies are ceasing their foraging activity cycle. Furthermore, the ending of A. striatus colonies foraging activity in the evenings also coincides with the beginning of A. lobicornis foraging. During autumn, colonies showed very scarce activity (< 15 ants / 5 minutes in any single colony). Daily and seasonal variations in nest maintenance activity were broadly similar to foraging activity patterns, though spanning larger time ranges than their foraging activity (starting earlier and finishing later).

The ants foraged within a particular temperature range that was relatively constant throughout the year and differed from its congener: A. striatus colonies foraged at higher temperatures than A. lobicornis in all seasons (26 - 45 °C vs. 16 - 35 °C, respectively).

Jofre et al. (2018) - Foraging behavior was studied in a natural reserve of San Luis, Argentina. The chaco vegetation found within the reserve had in the past been affected by overgrazing, fire, and logging. In addition to quantifying the plants selected by foragers, it was found that small nests of A. striatus harvested a greater percent of the plant species available in their foraging area and showed a higher level of selectivity than larger nests.

Male
Diploid males are known to occur in this species (found in 0.7% of 140 examined nests) (Araújo & Cavalli-Molina, 2001; Cournault & Aron, 2009).

Nomenclature

 * . Atta striata Roger, 1863a: 202 (w.q.m.) URUGUAY.
 * Combination in Atta (Oecodoma): Mayr, 1863: 458;
 * combination in Atta (Acromyrmex): Forel, 1885a: 361; Emery, 1888c: 357;
 * combination in Atta (Moellerius): Emery, 1905c: 42;
 * combination in Acromyrmex: Bruch, 1914: 217;
 * combination in Acromyrmex (Moellerius): Gallardo, 1916d: 338; Emery, 1924d: 351.
 * combination in Amoimyrmex: Cristiano, Cardoso & Sandoval, 2020: 667.
 * Status as species: Roger, 1863b: 35; Mayr, 1863: 458; Forel, 1885a: 361 (in key); Emery, 1888c: 357; Emery, 1888e: 690; Dalla Torre, 1893: 154; von Jhering, 1894: 388; Forel, 1895b: 139; Emery, 1905c: 42; Emery, 1906c: 166; Forel, 1912e: 181; Bruch, 1914: 217; Gallardo, 1916d: 338; Santschi, 1916e: 389; Emery, 1924d: 351; Santschi, 1925a: 389 (in key); Borgmeier, 1927c: 136; Kusnezov, 1953b: 338; Kusnezov, 1956: 34 (in key); Gonçalves, 1961: 129; Kempf, 1972a: 16; Zolessi & Abenante, 1977: 78; Zolessi, et al. 1988: 5; Fowler, 1988: 290; Cherrett & Cherrett, 1989: 52; Brandão, 1991: 323; Bolton, 1995b: 57; Wild, 2007b: 30.
 * Senior synonym of laeviventris: Fowler, 1988: 290; Brandão, 1991: 323; Bolton, 1995b: 57.
 * laeviventris. Acromyrmex (Moellerius) striatus var. laeviventris Santschi, 1925a: 388.
 * [First available use of Acromyrmex (Moellerius) striatus st. silvestrii var. laeviventris Santschi, 1920d: 380 (w.) ARGENTINA (Jujuy, Santa Fe); unavailable (infrasubspecific) name.]
 * Subspecies of striatus: Kempf, 1972a: 16.
 * Junior synonym of striatus: Fowler, 1988: 290; Brandão, 1991: 323; Bolton, 1995b: 55.

Karyotype


Amoimyrmex striatus shares the characteristics of both Acromyrmex and Atta, as it presents peculiarities such as its karyotype formula 2K = 20M + 2SM, indicating that A. striatus may be better classified as a genus distinct from its sibling leafcutter ants (Cristiano et al., 2013; de Castro et al., 2020). Cristiano, Cardoso & Sandoval (2020) transferred this species to the newly established genus Amoimyrmex.

References based on Global Ant Biodiversity Informatics

 * Badano, E.I., H.A. Regidor, H.A. Nunez, R. Acosta and E. Gianoli. 2005. Species richness and structure of ant communities in a dynamic archipelago: effects of island area and age. Journal of Biogeography
 * Bicho C. L., M. L. C. Brancao, and S. M. Pires. 2007. Mirmecofauna (Hymenoptera, Formicidae) em hospitais e postos de Saude no municipio de Bagé, RS. Arq. Inst. Biol., São Paulo 74(4): 373-377.
 * Bonetto A. A. 1959. Las hormigas "cortadoras" de la Provincia de Santa Fé (generos: Atta y Acromyrmex). Santa Fé, Argentina: Ministerio de Agricultura y Ganadería (Dirección General de Recurzos Naturales), 79 pp.
 * Bruch C. 1914. Catálogo sistemático de los formícidos argentinos. Revista del Museo de La Plata 19: 211-234.
 * Cardoso, D.C., T.G. Sobrinho and J.H. Schoereder. 2010. Ant community composition and its relationship with phytophysiognomies in a Brazilian Restinga. Insectes Sociaux 57:293-301
 * Cheli G. H., J. C. Corley, O. Bruzzone, M. Brío, F. Martínez, N. M. Roman, and I. Ríos. 2010. The ground-dwelling arthropod community of Península Valdés in Patagonia, Argentina. Journal of Insect Science 10:50 available online: insectsicence.org/10.50
 * Claver S., S. L. Silnik, and F. F. Campon. 2014. Response of ants to grazing disturbance at the central Monte Desert of Argentina: community descriptors and functional group scheme. J Arid Land 6(1): 117?127.
 * Claver S., and H. G. Gordon. 1993. The ant fauna (Hymenoptera, Formicidae) of the Nacunan Biosphere reserve. Naturalis Sao Paulo 18: 189-193.
 * Clemes Cardoso D., and J. H. Schoereder. 2014. Biotic and abiotic factors shaping ant (Hymenoptera: Formicidae) assemblages in Brazilian coastal sand dunes: the case of restinga in Santa Catarina. Florida Entomologist 97(4): 1443-1450.
 * Clemes Cardoso D., and M. Passos Cristiano. 2010. Myrmecofauna of the Southern Catarinense Restinga sandy coastal plain: new records of species occurrence for the state of Santa Catarina and Brazil. Sociobiology 55(1b): 229-239.
 * Cristiano M. P., D. Clemes Cardoso, T. M. Fernandes-Salomao, and J. Heinze. 2016. Integrating paleodistribution models and phylogeography in the grass-cutting ant Acromyrmex striatus (Hymenoptera: Formicidae) in southern lowlands of South America. PLoS ONE 11(1): e0146734
 * Cuezzo, F. 1998. Formicidae. Chapter 42 in Morrone J.J., and S. Coscaron (dirs) Biodiversidad de artropodos argentinos: una perspectiva biotaxonomica Ediciones Sur, La Plata. Pages 452-462.
 * Culebra Mason S., C. Sgarbi, J. Chila Covachina, J. M. Pena, N. Dubrovsky Berensztein, C. Margaria, and M. Ricci. 2017. Acromyrmex Mayr (Hymenoptera: Formicidae: Myrmicinae): species distribution patterns in the province of Buenos Aires, Argentina. Rev. Mus. Argentino Cienc. Nat. 19(2) 185-199.
 * Diehl-Fleig E. 2014. Termites and Ants from Rio Grande do Sul, Brazil. Sociobiology (in Press).
 * Diehl-Fleig, E. and A.M. de Aruajo. 1996. Haplometrosis and pleometrosis in the ant Acromyrmex striatus (Hymenoptera: Formicidae). Insectes Sociaux 43:47-51
 * Emery C. 1888. Formiche della provincia di Rio Grande do Sûl nel Brasile, raccolte dal dott. Hermann von Ihering. Bullettino della Società Entomologica Italiana 19: 352-366.
 * Emery C. 1906. Studi sulle formiche della fauna neotropica. XXVI. Bullettino della Società Entomologica Italiana 37: 107-194.
 * Farji Brener A. G., and A. Ruggiero. 1994. Leaf-cutting ants (Atta and Acromyrmex) inhabiting Argentina: patterns in species richness and geographical range sizes. Journal of Biogeography 21(4): 391-399.
 * Fernández, F. and S. Sendoya. 2004. Lista de las hormigas neotropicales. Biota Colombiana Volume 5, Number 1.
 * Fowler H. G. 1988. Taxa of the neotropical grass-cutting ants, Acromyrmex (Hymenoptera: Formicidae: Attini). Científica (Jaboticabal) 16: 281-295.
 * Garcia M., and E. M. Quiran. 2002. Preliminary list of Formicidae (Insecta: Hymenoptera) of Sierra de las Quijadas National Park (San Luis, Argentina). Gayana 66(1): 83-84.
 * Gonçalves C. R. 1961. O genero Acromyrmex no Brasil (Hym. Formicidae). Stud. Entomol. 4: 113-180.
 * Kempf, W.W. 1972. Catalago abreviado das formigas da regiao Neotropical (Hym. Formicidae) Studia Entomologica 15(1-4).
 * Kusnezov N. 1953. La fauna mirmecológica de Bolivia. Folia Universitaria. Cochabamba 6: 211-229.
 * Kusnezov N. 1956. Claves para la identificación de las hormigas de la fauna argentina. Idia 104-105: 1-56.
 * Kusnezov N. 1957. Die Solenopsidinen-Gattungen von Südamerika (Hymenoptera, Formicidae). Zoologischer Anzeiger 158: 266-280.
 * Kusnezov N. 1978. Hormigas argentinas: clave para su identificación. Miscelánea. Instituto Miguel Lillo 61:1-147 + 28 pl.
 * Murua A. F., F. Cuezzo, and J. C. Acosta. 1999. La fauna de hormigas del Gran Bajo Oriental del departamento Valle Fertíl (San Juan, Argentina). Revista de la Sociedad Entomológica Argentina 58(3/4): 135-138.
 * Osorio Rosado J. L, M. G. de Goncalves, W. Drose, E. J. Ely e Silva, R. F. Kruger, and A. Enimar Loeck. 2013. Effect of climatic variables and vine crops on the epigeic ant fauna (Hymenoptera: Formicidae) in the Campanha region, state of Rio Grande do Sul, Brazil. J Insect Conserv 17: 1113-1123.
 * Pall J. L. M., and E. M. Quiran. 2009. Redescripción de la obrera de Solenopsis leptanilloides (Hymenoptera: Formicidae) y primera cita de la provincia de La Pampa (Argentina). Revista de la Sociedad Entomológica Argentina 68: 381-383.
 * Pall J. L., R. G. Kihn, L. C. Arriaga, and E. Quiran. 2011. Report of the epigean arthropod fauna in the "Laguna Don Tomas", Santa Rosa (La Pampa, Argentina). Mun. Ent. Zool. 6(2): 905-911.
 * Pignalberi C. T. 1961. Contribución al conocimiento de los formícidos de la provincia de Santa Fé. Pp. 165-173 in: Comisión Investigación Científica; Consejo Nacional de Investigaciones Científicas y Técnicas (Argentina) 1961. Actas y trabajos del primer Congreso Sudamericano de Zoología (La Plata, 12-24 octubre 1959). Tomo III. Buenos Aires: Librart, 276 pp.
 * Quiran E. M., and A. A. Casadio. 1988. Lista preliminar anotada de los formicidos de la provincia de la Pampa. Rev. Fac. Agronomia UNLPam 3(1): 99-104.
 * Rosa da Silva R. 1999. Formigas (Hymenoptera: Formicidae) do oeste de Santa Catarina: historico das coletas e lista atualizada das especies do Estado de Santa Catarina. Biotemas 12(2): 75-100.
 * Santschi F. 1916. Formicides sudaméricains nouveaux ou peu connus. Physis (Buenos Aires). 2: 365-399.
 * Solomon S. E., C. Rabeling, J. Sosa-Calvo, C. Lopes, A. Rodrigues, H. L. Vasconcelos, M. Bacci, U. G. Mueller, and T. R. Schultz. 2019. The molecular phylogenetics of Trachymyrmex Forel ants and their fungal cultivars provide insights into the origin and coevolutionary history of ‘higher-attine’ ant agriculture. Systematic Entomology 44: 939–956.
 * Tizon F. R., D. V. Pelaez, and O. R. Elia. 2010. Effects of firebreaks on ant density (Hymenoptera, Formicidae) in a semiarid region, Argentina. Iheringia, Sér. Zool., Porto Alegre 100(3): 216-221.
 * Ulyssea M.A., C. E. Cereto, F. B. Rosumek, R. R. Silva, and B. C. Lopes. 2011. Updated list of ant species (Hymenoptera, Formicidae) recorded in Santa Catarina State, southern Brazil, with a discussion of research advances and priorities. Revista Brasileira de Entomologia 55(4): 603-611.
 * Varela, R.O. and R.C. Perera. 2003. Dispersal of Schinus fasciculatus Seeds by the Leaf-Cutting Ant Acromyrmex striatus in a Shrubland of the Dry Chaco, Argentina. Journal of Tropical Ecology 19 (1):91-94
 * Vittar, F. 2008. Hormigas (Hymenoptera: Formicidae) de la Mesopotamia Argentina. INSUGEO Miscelania 17(2):447-466
 * Vittar, F., and F. Cuezzo. "Hormigas (Hymenoptera: Formicidae) de la provincia de Santa Fe, Argentina." Revista de la Sociedad Entomológica Argentina (versión On-line ISSN 1851-7471) 67, no. 1-2 (2008).
 * Wild, A. L. "A catalogue of the ants of Paraguay (Hymenoptera: Formicidae)." Zootaxa 1622 (2007): 1-55.
 * Zolessi L. C. de, Y. P. Abenante, and M. E. de Philippi. 1988. Lista sistematica de las especies de Formicidos del Uruguay. Comun. Zool. Mus. Hist. Nat. Montev. 11: 1-9.
 * Zolessi L. C. de; Y. P. de Abenante, and M. E. Philippi. 1989. Catálogo sistemático de las especies de Formícidos del Uruguay (Hymenoptera: Formicidae). Montevideo: ORCYT Unesco, 40 + ix pp.
 * de Zolessi, L.C., Y.P. de Abenante and M.E. Philippi. 1987. Lista sistemática de las especies de formícidos del Uruguay. Comunicaciones Zoologicas del Museo de Historia Natural de Montevideo 11(165):1-9
 * de Zolessi, L.C., Y.P. de Abenante and M.E. Phillipi. 1989. Catalago Systematico de las Especies de Formicidos del Uruguay (Hymenoptera: Formicidae). Oficina Regional de Ciencia y Technologia de la Unesco para America Latina y el Caribe- ORCYT. Montevideo, Uruguay