Acromyrmex lobicornis

An inhabitant of desert areas, this fungus growing ant harvests vegetation from a large range of plants. Acromyrmex lobicorni form large colonies, ~10,000 workers in a mature colony, and forage in well defined columns.

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

Biology
Jofre et al. (2018) - Acromyrmex lobicornis is one of the most common leaf-cutting ant species in Argentina (Farji-Brener & Ruggiero, 1994). This species constructs nests with an external nest-mound (Farji-Brener, 2000; Bollazzi et al., 2008) that house about 10.000 workers (Jofré & Medina, 2012) and build well defined trails to forage. Acromyrmex lobicornis 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 Acromyrmex lobicornis foraging behavior in the Monte Desert in Argentina where this species co-occurs with Acromyrmex striatus. Acromyrmex lobicornis colonies actively foraged from spring to autumn, with occasional external activity during winter. Foraging intensity was highest during spring and summer, with up to 150 ants (foragers returning to the nest) / 5 minutes. During spring and summer, A. lobicornis foraged mostly during the night, starting at dusk and continuing for up to 16 hours until the next morning. Colonies switched to diurnal foraging in autumn, when temperatures are lower. 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 still showed considerably high foraging activity (up to 80 ants / 5 minutes). 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 and large nests showed similar feeding behavior.

Nomenclature

 *  lobicornis. Atta (Acromyrmex) lobicornis Emery, 1888c: 358 (w.) BRAZIL. Emery, 1905c: 52 (q.m.). Combination in Acromyrmex: Bruch, 1914: 216. [Incorrectly recorded from Ivory Coast: Santschi, 1928f: 209.] Senior synonym of bucki, rufidens: Gonçalves, 1961: 148. Current subspecies: nominal plus cochlearis, ferrugineus, pencosensis, pruinosior.
 * bucki. Acromyrmex bucki Wasmann, 1931: 106 (w.) BRAZIL. Junior synonym of lobicornis: Gonçalves, 1961: 148.
 * rufidens. Acromyrmex lobicornis var. rufidens Santschi, 1933e: 120 (w.) BRAZIL. Junior synonym of lobicornis: Gonçalves, 1961: 148.

References based on Global Ant Biodiversity Informatics

 * 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.
 * 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.
 * 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).
 * Drose W., L. R. Podgaiski, C. Fagundes Dias, M. de Souza Mendonca. 2019. Local and regional drivers of ant communities in forest-grassland ecotones in South Brazil: A taxonomic and phylogenetic approach. Plos ONE 14(4): e0215310.
 * 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. 1985. Leaf-cutting ants of the genera Atta and Acromyrmex of Paraguay (Hymenoptera, Formicidae) Dtsch. Ent. Z., N. F. 32(1-3): 19-34.
 * Gallardo A. 1915. Observaciones sobre algunas hormigas de la República Argentina. Anales del Museo Nacional de Historia Natural de Buenos Aires 27: 1-35.
 * Gallardo A. 1916. Notes systématiques et éthologiques sur les fourmis attines de la République Argentine. Anales del Museo Nacional de Historia Natural de Buenos Aires 28: 317-344.
 * 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).
 * Klingenberg, C. and C.R.F. Brandao. 2005. The type specimens of fungus growing ants, Attini (Hymenoptera, Formicidae, Myrmicinae) deposited in the Museu de Zoologia da Universidade de Sao Paulo, Brazil. Papeis Avulsos de Zoologia 45(4):41-50
 * Kusnezov N. 1953. La fauna mirmecológica de Bolivia. Folia Universitaria. Cochabamba 6: 211-229.
 * 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.
 * Loiacono M. S., C. B. Margaria, and D. A. Aquino. 2013. Diapriinae wasps (Hymenoptera: Diaprioidea: Diapriidae) associated with ants (Hymenoptera: Formicidae) in Argentina. Psyche http://dx.doi.org/10.1155/2013/320590
 * Marcus H. 1945. La diferencia en la fauna de las hormigas de Cochabamba y Liriuni. Revista de Agricultura 3: 28-29.
 * Masiulionis V. E., R. W. S. Weber, and F. C. Pagnocca. 2013. Foraging of Psilocybe basidiocarps by the leaf-cutting ant Acromyrmex lobicornis in Santa Fé, Argentina. SpringerPlus 2: 254.
 * Mayhe Nunes A. J., and E. Diehl-Fleig. 1994. Acromyrmex (Hymenoptera: Formicidae) distribution in Rio Grande do Sul, Brazil. Acta Biologica Leopoldensia 16(1): 115-118.
 * Medel R. G., and R. A. Vasquez. 1994. Comparative analysis of harvester ant assemblages of Argentinian and Chilean arid zones. Journal of Arid Anvironments 26: 363-371
 * 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.
 * 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.
 * Santschi F. 1912. Quelques fourmis de l'Amérique australe. Revue Suisse de Zoologie 20: 519-534.
 * Santschi F. 1922. Myrmicines, dolichodérines et autres formicides néotropiques. Bulletin de la Société Vaudoise des Sciences Naturelles 54: 345-378.
 * Santschi F. 1925. Fourmis des provinces argentines de Santa Fe, Catamarca, Santa Cruz, Córdoba et Los Andes. Comunicaciones del Museo Nacional de Historia Natural "Bernardino Rivadavia" 2: 149-168.
 * 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