Acromyrmex ambiguus

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Acromyrmex ambiguus
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Attini
Genus: Acromyrmex
Species: A. ambiguus
Binomial name
Acromyrmex ambiguus
(Emery, 1888)

Acromyrmex ambiguus casent0281786 p 1 high.jpg

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Specimen Labels

Synonyms

Acromyrmex ambiguus is common in Rio Grande do Sul, Brazil. They harvest monocotyledonous leaves (Loeck and Grutzmacher 2001) and masticate their collected plant material into tiny pieces to create the substrate for growing their fungal gardens. A molecular study of co-occuring populations of this species and Acromyrmex heyeri showed both of these species are cultivating Leucoagaricus gongylophorus but that there are differences in the fungal strains used by the two ant species (Pereira et al. 2015).

Identification

Distribution

Latitudinal Distribution Pattern

Latitudinal Range: -22.809943° to -31.648611°.

   
North
Temperate
North
Subtropical
Tropical South
Subtropical
South
Temperate

Distribution based on Regional Taxon Lists

Neotropical Region: Argentina, Brazil (type locality), Paraguay, Uruguay.

Distribution based on AntMaps

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Distribution based on AntWeb specimens

Check data from AntWeb

Countries Occupied

Number of countries occupied by this species based on AntWiki Regional Taxon Lists. In general, fewer countries occupied indicates a narrower range, while more countries indicates a more widespread species.
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Estimated Abundance

Relative abundance based on number of AntMaps records per species (this species within the purple bar). Fewer records (to the left) indicates a less abundant/encountered species while more records (to the right) indicates more abundant/encountered species.
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Biology

Explore-icon.png Explore Fungus Growing 
For additional details see Fungus growing ants.

A handful of ant species (approx. 275 out of the known 15,000 species) have developed the ability to cultivate fungus within their nests. In most species the fungus is used as the sole food source for the larvae and is an important resource for the adults as well. Additionally, in a limited number of cases, the fungus is used to construct part of the nest structure but is not as a food source.

These fungus-feeding species are limited to North and South America, extending from the pine barrens of New Jersey, United States, in the north (Trachymyrmex septentrionalis) to the cold deserts in Argentina in the south (several species of Acromyrmex). Species that use fungi in nest construction are known from Europe and Africa (a few species in the genera Crematogaster, Lasius).


The details of fungal cultivation are rich and complex. First, a wide variety of materials are used as substrate for fungus cultivating. The so-called lower genera include species that prefer dead vegetation, seeds, flowers, fruits, insect corpses, and feces, which are collected in the vicinity of their nests. The higher genera include non leaf-cutting species that collect mostly fallen leaflets, fruit, and flowers, as well as the leafcutters that collect fresh leaves from shrubs and trees. Second, while the majority of fungi that are farmed by fungus-feeding ants belong to the family Lepiotaceae, mostly the genera Leucoagaricus and Leucocoprinus, other fungi are also involved. Some species utilise fungi in the family Tricholomataceae while a few others cultivate yeast. The fungi used by the higher genera no longer produce spores. Their fungi produce nutritious and swollen hyphal tips (gongylidia) that grow in bundles called staphylae, to specifically feed the ants. Finally, colony size varies tremendously among these ants. Lower taxa mostly live in inconspicuous nests with 100–1000 individuals and relatively small fungus gardens. Higher taxa, in contrast, live in colonies made of 5–10 million ants that live and work within hundreds of interconnected fungus-bearing chambers in huge subterranean nests. Some colonies are so large, they can be seen from satellite photos, measuring up to 600 m3.

Based on these habits, and taking phylogenetic information into consideration, these ants can be divided into six biologically distinct agricultural systems (with a list of genera involved in each category):

Nest Construction

A limited number of species that use fungi in the construction of their nests.

Lower Agriculture

Practiced by species in the majority of fungus-feeding genera, including those thought to retain more primitive features, which cultivate a wide range of fungal species in the tribe Leucocoprineae.

Coral Fungus Agriculture

Practiced by species in the Apterostigma pilosum species-group, which cultivate fungi within the Pterulaceae.

Yeast Agriculture

Practiced by species within the Cyphomyrmex rimosus species-group, which cultivate a distinct clade of leucocoprineaceous fungi derived from the lower attine fungi.

Generalized Higher Agriculture

Practiced by species in several genera of non-leaf-cutting "higher attine" ants, which cultivate a distinct clade of leucocoprineaceous fungi separately derived from the lower attine fungi.

Leaf-Cutter Agriculture

A subdivision of higher attine agriculture practiced by species within several ecologically dominant genera, which cultivate a single highly derived species of higher attine fungus.

Note that the farming habits of Mycetagroicus (4 species) are unknown. Also, while species of Pseudoatta (2 species) are closely related to the fungus-feeding genus Acromyrmex, they are social parasites, living in the nests of their hosts and are not actively involved in fungus growing. ‎

Association with Other Organisms

Explore-icon.png Explore: Show all Associate data or Search these data. See also a list of all data tables or learn how data is managed.
  • This species is a host for the diapriid wasp Szelenyiopria lucens (a parasite) in Brazil, Uruguay (Loiacono, 1987; Loiacono et al., 2013; Gonzalez et al., 2016).
  • This species is a host for the histerid beetle Euspilotus myrmecophilus (a myrmecophile) in Argentina, Brazil, Uruguay (Lackner, 2014; Lackner & Arriagada, 2020).

Castes

Nomenclature

The following information is derived from Barry Bolton's Online Catalogue of the Ants of the World.

  • ambiguus. Atta (Acromyrmex) lundi var. ambigua Emery, 1888c: 358 (w.) BRAZIL (Rio Grande do Sul).
    • Goni, et al. 1983: 365 (k.).
    • Combination in Acromyrmex: Bruch, 1914: 216.
    • Subspecies of lundii: Dalla Torre, 1893: 153; Forel, 1895b: 139.
    • Status as species: Emery, 1905c: 50; Emery, 1906c: 166; Bruch, 1914: 216; Gallardo, 1916d: 328; Emery, 1924d: 348; Santschi, 1925a: 383; Borgmeier, 1927c: 129; Kusnezov, 1956: 35 (in key); Gonçalves, 1961: 131; Kempf, 1972a: 11; Zolessi & Abenante, 1977: 80; Zolessi, et al. 1988: 4; Cherrett & Cherrett, 1989: 50; Brandão, 1991: 322; Bolton, 1995b: 54; Wild, 2007b: 30.
    • Senior synonym of erectus: Gonçalves, 1961: 131; Kempf, 1972a: 11; Bolton, 1995b: 54.
  • erectus. Acromyrmex ambiguus var. erectus Santschi, 1925a: 384, fig. 2 (w.) BRAZIL (São Paulo).
    • Subspecies of ambiguus: Borgmeier, 1927c: 129.
    • Junior synonym of ambiguus: Gonçalves, 1961: 131; Kempf, 1972a: 11; Bolton, 1995b: 55.

Description

Karyotype

  • 2n = 38, karyotype = 2M+6SM+16ST+14A (Uruguay) (Goñi et al., 1984).
  • 2n = 38, karyotype = 14M + 12SM + 8ST + 4A (Brazil) (de Castro et al., 2020).

References

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.
  • Brandao, C.R.F. 1991. Adendos ao catalogo abreviado das formigas da regiao neotropical (Hymenoptera: Formicidae). Rev. Bras. Entomol. 35: 319-412.
  • Bruch C. 1914. Catálogo sistemático de los formícidos argentinos. Revista del Museo de La Plata 19: 211-234.
  • 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.
  • 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.
  • Gonçalves C. R. 1961. O genero Acromyrmex no Brasil (Hym. Formicidae). Stud. Entomol. 4: 113-180.
  • Kempf W. W. 1978. A preliminary zoogeographical analysis of a regional ant fauna in Latin America. 114. Studia Entomologica 20: 43-62.
  • Kempf, W.W. 1972. Catalago abreviado das formigas da regiao Neotropical (Hym. Formicidae) Studia Entomologica 15(1-4).
  • Kusnezov N. 1956. Claves para la identificación de las hormigas de la fauna argentina. Idia 104-105: 1-56.
  • Kusnezov N. 1978. Hormigas argentinas: clave para su identificación. Miscelánea. Instituto Miguel Lillo 61:1-147 + 28 pl.
  • Lutinski J. A., B. C. Lopes, and A. B. B.de Morais. 2013. Diversidade de formigas urbanas (Hymenoptera: Formicidae) de dez cidades do sul do Brasil. Biota Neotrop. 13(3): 332-342.
  • 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.
  • 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.
  • Rodrigues, A., M. Bacci, Jr., U.G. Mueller, A. Ortiz and F.C. Pagnocca. 2008. Microfungal “Weeds” in the Leafcutter Ant Symbiosis. Microbial Ecology 56:604-614
  • Rosado J. L. O., M. G. de Gonçalves, W. Dröse, E. J. E. e Silva, R. F. Krüger, R. M. Feitosa, and A. E. Loeck. 2012. Epigeic ants (Hymenoptera: Formicidae) in vineyards and grassland areas in the Campanha region, state of Rio Grande do Sul, Brazil. Check List, Journal of species lists and distribution 8(6): 1184-1189.
  • Santos Rando J. S., and L. C. Forti. 2005. Occurrence of ants Acromyrmex Mayr, 1865 in some cities of Brasil. Maringá 27(2): 129-133.
  • Santschi F. 1925. Revision du genre Acromyrmex Mayr. Revue Suisse de Zoologie 31: 355-398.
  • 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.
  • 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 Abreu J. M., and J. H. C. Delabie. 1986. Controle das formigas cortadeiras em plantios de cacau. Revista Theobroma 16(4): 199-211.
  • 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