Acromyrmex
Acromyrmex | |
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Acromyrmex versicolor | |
Scientific classification | |
Kingdom: | Animalia |
Phylum: | Arthropoda |
Class: | Insecta |
Order: | Hymenoptera |
Family: | Formicidae |
Subfamily: | Myrmicinae |
Tribe: | Attini |
Genus: | Acromyrmex Mayr, 1865 |
Type species | |
Formica hystrix, now Acromyrmex hystrix | |
Subgenera | |
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Diversity | |
55 species (Species Checklist, Species by Country) |
Evolutionary Relationships | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Based on Ward et al. (2014), Blaimer et al. (2018), Li et al. (2018) and Cristiano et al. (2020). |
A genus of fungus growing ants. Primarily a Neotropical group, Acromyrmex occurs from the southern USA south to southern South America. They cultivate fungus within their nests and, like Atta, they are true leaf-cutters. Most Acromyrmex inhabit tropical forests, grasslands, and disturbed areas. Acromyrmex versicolor is atypical in that it is found in dry desert areas of the southwestern USA and northern Mexico.
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Identification
The genus Acromyrmex occupies a morphological "middle ground" between the highly polymorphic genus Atta and the monomorphic genus Trachymyrmex. Acromyrmex is separated from Atta by the presence of 3 pairs of spines or teeth on the promesonotum (only 2 pairs in Atta), and from Trachymyrmex by the presence of spines or teeth on the promesonotum (rather than tubercles), by the absence of shallow antennal scrobes (often present in Trachymyrmex), and its polymorphic worker caste (monomorphic in Trachymyrmex).
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See images of species within this genus |
Keys including this Genus
Distribution
Distribution and Richness based on AntMaps
Biology
Longino (Ants of Costa Rica) - Acromyrmex species are true leaf cutters. Compared to Atta, they have a greater predilection for flowers and fruits. Their colonies are smaller (thousands of workers rather than millions), and foraging columns are usually single file and sparse. Their nests are usually in pre-formed cavities, and they do little excavating of their own.
Morphologically they are sandwiched between Atta and Trachymyrmex. Atta have very large colonies, strong worker size polymorphism, and a smooth gastral dorsum. Trachymyrmex have smaller colonies, usually smaller monomorphic workers, and a tuberculate gastral dorsum. Acromyrmex have intermediate colony sizes, strong worker polymorphism (but the major workers are not as highly differentiated as Atta majors), and the gaster is tuberculate. Single workers of Acromyrmex can be difficult to differentiate from Trachymyrmex in a key.
In Costa Rica there are few species of Acromyrmex. In lowland and seasonally dry habitats there are usually one or two forms of the Acromyrmex octospinosus species complex. In moist to wet montane areas Acromyrmex coronatus dominates.
Schultz et al. (1998) have discovered cryptic species in the A. octospinosus complex in Panama, and one should expect similar complexity to occur in Costa Rica. I recognize three species in the complex in Costa Rica (octospinosus, Acromyrmex echinatior, Acromyrmex volcanus), but the morphological basis for the distinctions is slight and some concentrated research on the group could easily redraw the species boundaries.
There is a large literature on Acromyrmex that is not reviewed or cited here.
Association with Other Organisms
Species Uncertain
- An unknown species is a host for the histerid beetle Euspilotus latimanus (a myrmecophile) in Brazil (Arriagada, 1987; Lackner, 2014).
All Associate Records for Genus
Taxon | Relationship | Associate Type | Associate Taxon | Associate Relationship | Locality | Source | Notes |
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Acromyrmex | host | histerid beetle | Euspilotus latimanus | myrmecophile | Brazil | Arriagada, 1987; Lackner, 2014 | |
Acromyrmex ambiguus | host | diapriid wasp | Gymnopria lucens | parasite | Brazil, Uruguay | Loiacono, 1987; Gonzalez et al., 2016 | |
Acromyrmex ambiguus | host | histerid beetle | Euspilotus myrmecophilus | myrmecophile | Argentina, Brazil, Uruguay | Lackner, 2014; Lackner & Arriagada, 2020 | |
Acromyrmex ameliae | inquiline | ant | Acromyrmex subterraneus | host | |||
Acromyrmex balzani | host | ant | Pseudoatta argentina | workerless inquiline | Needs confirmation | ||
Acromyrmex charruanus | inquiline | ant | Acromyrmex heyeri | host | |||
Acromyrmex echinatior | host | ant | Acromyrmex insinuator | inquiline | |||
Acromyrmex fowleri | workerless inquiline | ant | Acromyrmex rugosus | host | |||
Acromyrmex heyeri | host | ant | Acromyrmex charruanus | workerless inquiline | |||
Acromyrmex heyeri | host | ant | Pseudoatta argentina | workerless inquiline | |||
Acromyrmex insinuator | inquiline | ant | Acromyrmex echinatior | host | |||
Acromyrmex insinuator | inquiline | ant | Acromyrmex octospinosus | host | |||
Acromyrmex lobicornis | host | diapriid wasp | Szelenyiopria pampeana | parasite | Argentina | Loiacono, 2013; Gonzalez et al., 2016 | |
Acromyrmex lobicornis | host | diapriid wasp | Trichopria formicans | parasite | Argentina | Loiacono, 2013; Gonzalez et al., 2016 | |
Acromyrmex lundii | host | ant | Pseudoatta argentina | workerless inquiline | |||
Acromyrmex lundii | host | diapriid wasp | Bruchopria hexatoma | parasite | Argentina | Loiacono, 2013; Gonzalez et al., 2016 | |
Acromyrmex lundii | host | diapriid wasp | Doliopria myrmecobia | parasite | Argentina | Loiacono, 2013; Gonzalez et al., 2016 | |
Acromyrmex lundii | host | histerid beetle | Euspilotus myrmecophilus | myrmecophile | Argentina, Brazil, Uruguay | Lackner, 2014; Lackner & Arriagada, 2020 | |
Acromyrmex octospinosus | host | ant | Acromyrmex insinuator | inquiline | not able to reproduce in ''Acromyrmex octospinosus'' colonies | ||
Acromyrmex subterraneus | host | ant | Acromyrmex ameliae | workerless inquiline | |||
Acromyrmex subterraneus | host | fungus | Aspergillus flavus | pathogen | Sales & Toledo, 2020 | ||
Acromyrmex subterraneus | host | fungus | Metarhizium anisopliae | pathogen | Sales & Toledo, 2020 |
Castes
Morphology
Worker Morphology
- Antennal segment count: 11
- Antennal club: gradual
- Palp formula: 4,2
- Total dental count: 8-11
- Spur formula: 0, 0
- Eyes: present
- Scrobes: absent
- Caste: polymorphic
Karyotype
All Karyotype Records for Genus
Taxon | Haploid | Diploid | Karyotype | Locality | Source | Notes |
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Acromyrmex ambiguus | 38 | 14M + 12SM + 8ST + 4A | Brazil | de Castro et al., 2020 | ||
Acromyrmex ambiguus | 38 | 2M+6SM+16ST+14A | Uruguay | Goñi et al., 1984 | ||
Acromyrmex ameliae | 36 | Brazil | Cardoso et al. 2018; de Castro et al., 2020 | |||
Acromyrmex aspersus | 38 | 8M+10SM+16ST+4A | Brazil | Teixeira et al., 2017 | ||
Acromyrmex balzani | 38 | 12M+10SM+14ST+2A | Brazil | Barros et al., 2016 | ||
Acromyrmex balzani | 38 | 12M+10SM+14ST+2A | French Guiana | Aguiar et al., 2020 | ||
Acromyrmex coronatus | 19 | 38 | 12M+8SM+16ST+2A | Brazil | Barros et al., 2016 | |
Acromyrmex crassispinus | 38 | Brazil | Fadini & Pompolo, 1996 | |||
Acromyrmex crassispinus | 38 | 12M + 20SM + 4ST + 2A | Brazil | de Castro et al., 2020 | ||
Acromyrmex disciger | 38 | 10M+12SM+14ST+2A | Brazil | Barros et al., 2016 | ||
Acromyrmex echinatior | 38 | 8M+6SM+14ST+10A | Brazil | Barros et al., 2016 | ||
Acromyrmex heyeri | 38 | 2M+6SM+16ST+14A | Brazil; Uruguay | Goni et al., 1983; SantosColares et al., 1997 | ||
Acromyrmex hispidus | 38 | 2M+6SM+16ST+14A | Uruguay | Goni et al., 1983 | ||
Acromyrmex lundii | 38 | 10M + 14SM + 10ST + 4A | Brazil | de Castro et al., 2020 | ||
Acromyrmex niger | 38 | 12M+14SM+10ST+2A | Brazil | Barros et al., 2016 | ||
Acromyrmex nigrosetosus | 38 | 12M + 14SM + 10ST + 2A | Brazil | de Castro et al., 2020 | ||
Acromyrmex rugosus | 38 | 16M+12SM+8ST+2A | Brazil | Barros et al., 2016 | ||
Acromyrmex subterraneus | 38 | Brazil | Fadini & Pompolo, 1996 | |||
Acromyrmex subterraneus | 38 | 14M + 18SM + 4ST + 2A | Brazil | de Castro et al., 2020 | ||
Acromyrmex subterraneus molestans | 38 | 10M+10SM+16ST+2A | Brazil | Fadini & Pompolo, 1996; Teixeira et al., 2017 |
Nomenclature
The following information is derived from Barry Bolton's Online Catalogue of the Ants of the World.
- ACROMYRMEX [Myrmicinae: Attini]
- Acromyrmex Mayr, 1865: 83 [as subgenus of Atta]. Type-species: Formica hystrix, by monotypy.
- Acromyrmex raised to genus: Emery, 1913b: 251.
- Subgenera of Acromyrmex: nominal plus Moellerius.
References
- Arriagada, G. 1987. Notas sininimicas y datos distribucionales de Saprininae neotropicales. Revista Chilena de Entomologia 15: 61–70.
- Ashmead, W. H. 1905c. A skeleton of a new arrangement of the families, subfamilies, tribes and genera of the ants, or the superfamily Formicoidea. Can. Entomol. 37: 381-384 (page 384, Acromyrmex in Cryptoceridae, Attinae)
- Bolton, B. 2003. Synopsis and Classification of Formicidae. Mem. Am. Entomol. Inst. 71: 370pp (page 197, Acromyrmex as genus of Attini)
- Cherrett, J. M.; Cherrett, F. J. 1989. A bibliography of the leaf-cutting ants, Atta spp. and Acromyrmex spp., up to 1975. Overseas Dev. Nat. Resour. Inst. Bull. 14: 1-58 (page 1, Bibliography 1. Subgenera of Acromyrmex:nominal plus Moellerius)
- Cristiano, M.P., Cardoso, D.C., Sandoval‐Gómez, V.E., Simões‐Gomes, F.C. 2020. Amoimyrmex Cristiano, Cardoso, Sandoval, gen. nov. (Hymenoptera: Formicidae): a new genus of leaf‐cutting ants revealed by multilocus molecular phylogenetic and morphological analyses. Austral Entomology 59, 643–676 (doi:10.1111/aen.12493).
- Dalla Torre, K. W. von. 1893. Catalogus Hymenopterorum hucusque descriptorum systematicus et synonymicus. Vol. 7. Formicidae (Heterogyna). Leipzig: W. Engelmann, 289 pp. (page 151, Acromyrmex as subgenus of Atta)
- Emery, C. 1895l. Die Gattung Dorylus Fab. und die systematische Eintheilung der Formiciden. Zool. Jahrb. Abt. Syst. Geogr. Biol. Tiere 8: 685-778 (page 770, Acromyrmex in Myrmicinae, Attini; Acromyrmex as subgenus of Atta)
- Emery, C. 1905f. Revisione delle specie del genere Atta appartenenti ai sottogeneri Moellerius e Acromyrmex. Mem. R. Accad. Sci. Ist. Bologna (6)2:39-54 (page 39, Acromyrmex as subgenus of Atta)
- Emery, C. 1913c. Études sur les Myrmicinae. [V-VII.]. Ann. Soc. Entomol. Belg. 57: 250-262 (page 251, Acromyrmex raised to genus; Acromyrmex in Myrmicinae, Attini)
- Emery, C. 1914e. Intorno alla classificazione dei Myrmicinae. Rend. Sess. R. Accad. Sci. Ist. Bologna Cl. Sci. Fis. (n.s.) 18: 29-42 (page 42, Acromyrmex in Myrmicinae, Attini)
- Emery, C. 1924f [1922]. Hymenoptera. Fam. Formicidae. Subfam. Myrmicinae. [concl.]. Genera Insectorum 174C: 207-397 (page 347, Acromyrmex in Myrmicinae, Attini; Acromyrmex as genus)
- Forel, A. 1885a [1884]. Études myrmécologiques en 1884 avec une description des organes sensoriels des antennes. Bull. Soc. Vaudoise Sci. Nat. 20: 316-380 (page 354, Acromyrmex as subgenus of Atta)
- Forel, A. 1893b. Sur la classification de la famille des Formicides, avec remarques synonymiques. Ann. Soc. Entomol. Belg. 37: 161-167 (page 163, Acromyrmex as subgenus of Atta)
- Forel, A. 1899d. Formicidae. [part]. Biol. Cent.-Am. Hym. 3: 25-56 (page 30, Acromyrmex as subgenus of Atta)
- Forel, A. 1913c. Fourmis de Nigérie. Rev. Zool. Afr. (Bruss.) 2: 352-353 (page 251, Acromyrmex divided into subgenera Acromyrmex Mayr and Moellerius Forel)
- Forel, A. 1917. Cadre synoptique actuel de la faune universelle des fourmis. Bull. Soc. Vaudoise Sci. Nat. 51: 229-253 (page 247, Acromyrmex in Myrmicinae, Attini; Acromyrmex as genus)
- Fowler, H. G. 1988b. Taxa of the neotropical grass-cutting ants, Acromyrmex (Hymenoptera: Formicidae: Attini). Científica (Jaboticabal) 16: 281-295 (page 284, Partial revision of genus)
- Gonçalves, C. R. 1961. O genero Acromyrmex no Brasil (Hym. Formicidae). Stud. Entomol. 4: 113-180 (page 113, Revision of Brazilian fauna)
- Lackner, T. 2014. Phylogeny of the Saprininae reveals interesting ecological shifts in the history of the subfamily (Coleoptera: Histeridae). Zoological Journal of the Linnean Society 172: 521–555.
- Mayr, G. 1865. Formicidae. In: Reise der Österreichischen Fregatte "Novara" um die Erde in den Jahren 1857, 1858, 1859. Zoologischer Theil. Bd. II. Abt. 1. Wien: K. Gerold's Sohn, 119 pp. (page 83, Acromyrmex as subgenus of Atta)
- Mueller, U.G., Schultz, T.R., Currie, C.R., Adams, R.M.M., Malloch, D. 2001. The origin of the attine ant-fungus mutualism. The Quarterly Review of Biology 76, 169-197.
- Santschi, F. 1925a. Revision du genre Acromyrmex Mayr. Rev. Suisse Zool. 31: 355-398 (page 355, 388, Key to species (out of date); Acromyrmex as genus)
- Wheeler, W. M. 1907d. The fungus-growing ants of North America. Bull. Am. Mus. Nat. Hist. 23: 669-807 (page 670, Acromyrmex as subgenus of Atta)
- Wheeler, W. M. 1910b. Ants: their structure, development and behavior. New York: Columbia University Press, xxv + 663 pp. (page 141, Acromyrmex as subgenus of Atta)
- Wheeler, W. M. 1922i. Ants of the American Museum Congo expedition. A contribution to the myrmecology of Africa. VII. Keys to the genera and subgenera of ants. Bull. Am. Mus. Nat. Hist. 45: 631-710 (page 669, Acromyrmex in Myrmicinae, Attini)
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