Mycetomoellerius holmgreni

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Mycetomoellerius holmgreni
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Attini
Genus: Mycetomoellerius
Species: M. holmgreni
Binomial name
Mycetomoellerius holmgreni
(Wheeler, W.M., 1925)

Trachymyrmex holmgreni casent0178106 profile 1.jpg

Trachymyrmex holmgreni casent0178106 dorsal 1.jpg

Specimen labels

This fungus-growing ant forms small soil nests in sandy soils. Their nest entrances are marked by a turret of grass, straw and sand. The architecture and demography of nests vary between season. In autumn, nests have fewer fungus chambers and many winged ants, while in the spring, there are more fungus chambers and a significant number of immature individuals. This indicates that M. holmgreni seems to invest in reproduction during the autumn and establishes new nests during the winter, which promotes growth during the spring and summer.

Identification

A member of the Iheringi species group. Mayhe-Nunes and Brandão (2005) - The most useful character to distinguish this species from the other members of the lheringi group is the shape of the lobes on the antennal scapes. Among the species that lack pilosity on the mesopleura, it also can be distinguished from Mycetomoellerius pruinosus, which has triangular frontal lobes. It differs from Mycetomoellerius tucumanus by the shape of the small projections on petiolar node, one or two spine-like pairs in M. holmgreni and one tooth-like pair in M. tucumanus.

Keys including this Species

Distribution

From Misiones Province in Argentina to northern Brazil.

Latitudinal Distribution Pattern

Latitudinal Range: -2.46079° to -31.38333333°.

   
North
Temperate
North
Subtropical
Tropical South
Subtropical
South
Temperate

Distribution based on Regional Taxon Lists

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

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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Habitat

This is a widely distributed ant that has been found in savanna, forest, restinga and dune habitats.

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. ‎

Albuquerque et al. 2018. Mycetomoellerius holmgreni nest. a Excavated nest; b Small straw turret at a single entrance hole; c Chamber 2 of a nest, dome-shaped; and d Fungus garden suspended from roots on the walls of the chamber.

Mayhe-Nunes and Brandão (2005) - The nest found at Santa Barbara do Monte Verde. Minas Gerais State, by one of us (AJMN) was excavated in sandy soil, in an area with few bushes and scarce low vegetation, about 1100 meters above sea level. The entrance hole was longer than broad (6 x 2cm) and in one of the sides had a tower of 1cm height, built with mixed grass straws and sand. The internal structure resembles that of nests of other Mycetomoellerius species, such as Mycetomoellerius pruinosus discovered by Gallardo (1916), as well as Mycetomoellerius turrifex described by Wheeler (1907). The seven alternating spheroidal chambers found were vertically disposed, with the following approximate measures: first chamber (3 x 3cm) about 5cm deep, second (7 x 7cm) to 10cm, third (5 x 5cm) to 20cm, fourth (9 x 7cm) to 30cm, fifth (7 x 5cm) to 40cm, sixth (5 x 5cm) to 50cm, and seventh (7 x 5cm) to 60 cm. The grayish fungus garden was laminated and set vertically, an appearance characteristic of grass use as fungal substrate. The first chamber had several pupae and little fungus hanging from the roof, suspended by thin roots. In the second chamber, a bulky fungus garden was also hung from the roof by roots. Equally, in the three following chambers, the gardens were big, however rested in the bottom of the chambers. The queen was in the fourth chamber; in the last two chambers, small amounts of fungus were found. Besides these chambers, five more possible trash chambers were observed containing a dark brown material, but without ants corpses. During the excavation, the workers do not feign death, a common behavior of other Mycetomoellerius. The appearance of the fungus garden and the use of grass straw to build the tower in the entrance of the nest corroborate Goncalves (1975) observations on M. holmgreni cutting fresh leaves of the grass Paspalum ancylocarpum.

Cristiano et al. (2018) - This fungus-growing ant forms small soil nests in sandy soils. Their nest entrances are marked by a turret of grass, straw and sand. The architecture and demography of nests vary between season. In autumn, nests have fewer fungus chambers and many winged ants, while in the spring, there are more fungus chambers and a significant number of immature individuals. This indicates that M. holmgreni seems to invest in reproduction during the autumn and establishes new nests during the winter, which promotes growth during the spring and summer.

Albuquerque et al. (2018) - A nest survey in Itapeva State Park (Rio Grande do Sul state, Brazil) collected nest attributes from 10 colonies and demographic information from 4 colonies. Colony sizes were: 294-581 workers, 20-107 pupae, 8-41 larvae, 0-27 males and 4-54 alate females. Dry and wet weight of the various castes were calculated and spatial aspects of the nest detailed (diameters of nest holes, chamber sizes, etc.). Colonies had a single nest entrance and typically had a small turret that was surrounding by a horeshoe shaped mound.

Castes

Queen

Trachymyrmex holmgreni queen.jpgWings Trachymyrmex holmgreni.jpg
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Male

Trachymyrmex holmgreni male.jpg
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Phylogeny

Mycetomoellerius

Mycetomoellerius urichii

Mycetomoellerius papulatus

Mycetomoellerius papulatus

Mycetomoellerius holmgreni

Mycetomoellerius cirratus

Mycetomoellerius kempfi

Mycetomoellerius iheringi

Mycetomoellerius sp. near cirratus

Mycetomoellerius ruthae

Mycetomoellerius jamaicensis

Mycetomoellerius atlanticus

Mycetomoellerius near haytianus

Mycetomoellerius opulentus

Mycetomoellerius dichrous

Mycetomoellerius relictus

Mycetomoellerius turrifex

Mycetomoellerius zeteki

Based on Micolino et al., 2020 (selected species only).

Nomenclature

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

  • holmgreni. Trachymyrmex holmgreni Wheeler, W.M. 1925a: 37 (w.) BOLIVIA.
    • Mayhé-Nunes & Brandão, 2005: 282 (q.m.).
    • Combination in Mycetomoellerius: Solomon et al., 2019: 948.

Unless otherwise noted the text for the remainder of this section is reported from the publication that includes the original description.

Description

Worker

Mayhe-Nunes and Brandão (2005) - TL 4.1-4.5; HL 1.12-1.34: HW 1.05-1.22; IFW 0.66-0.78; ScL 0.91-0.98; TrL 1.58-1.75; HfL 1.43- 1.58. Dark to reddish brown, sometimes with lighter head or darker gaster. Integument fine and indistinctly shagreened, opaque. Hairs moderately scarce on the body, short and erect or curved on appendages; hook-like mixed with oblique to decumbent hairs on gaster and other parts of body; fine pubescence restricted to funiculus.

Hlead in full face view little longer than broad (CI 95). Mandible smooth and shining except laterally on base where it is finely transversely striate, and near the masticatory margin, which bears the apical and 8 teeth gradually diminishing towards the base. Frontal lobe sub-triangular, moderately expanded laterad (FLI 65), backwards directed and laterally subdentate; anterior border straight; posterior border weakly concave. Frontal carina diverging caudad, fading out a little before the apex of scrobe. Front and vertex with weak longitudinal gulae. Posterior third of antennal scrobe weakly delimited by the frontal carina and extension of the preocular ones. Supraocular projection as bifid or truncated spine. Occiptal corner smoothly rounded full-face view, surmounted by stout tubercles. Occiput notched in the middle. Occipital tooth developed as a stout rather smooth spine-like projection. Inferior occipital corner with carina. Eye weakly convex, no more than 14 facets in a row across the greatest diameter. Antennal scape surpassing the occipital corner by nearly ¼ of its length, when laid back over head as much as possible; basal lobe perpendicularly enlarged, its inner projection bigger than the external ones, prolonged towards the head's middle when the scape is lodged in the scrobe: anterior surface surmounted by small tubercles and ridges.

Alitrunk. Pronotum with marked humeral angle; antero-inferior corner armed with a triangular and flattened spine-like projection; lateral spines long; median projections as two separated small truncated, bifid or simple spines. First pair of mesonotal projections similar to pronotal lateral ones; two longitudinal rows bearing three small teeth; the second and third pairs vestigial. Mesopleurae practically without hairs; blunt teeth-like projection on superior border of katepisternum. Alitrunk weakly constricted dorso-laterally at the shallowly impressed metanotal groove. Basal face of propodeum narrow, laterally delimited by a row of small teeth; slender propodeal spines longer than other dorsal projections of alitrunk.

Waist and gaster. Petiole shortly pedunculate, the node proper as long as broad, with one pair of small spines backwards directed, inserted near the posterior border; subpetiolar process vestigial. Postpetiole as long as broad, shallowly excavated above; posterodorsal border straight; postero-lateral corner without projections. Gaster opaque with minute piligerous tubercles randomly distributed in the tergum 1.

Queen

Mayhe-Nunes and Brandão (2005) - TL 5.6-5.9; HL 1.42- 1.51; HW 1.28-1.34; IFW 0.77-0.82; ScL 0.92-0.95; TrL 2.02-2.11; HfL 1.52-1.62; FWL 5.91-6.09; HWL 3.95-4.09. With the same general distinguishing characters of the workers, with the following differences: Thre ocelli on vertex, the lateral ones smaller. Pronotum with a pair of strong and acute scapular spines, directed out and forwards, and with a pair of inferior spines pointed down and forwards, smaller than the scapular ones. Mesoscutum surmounted by conspicuous tubercles, but without notable dorsal projections. With the alitrunk in dorsal view, very shallow parapses delimited by the parapsidial furrows; mesothoracic paraptera more or less impressed, with a narrow median portion; scutellum ending in a pair of moderately stout and acute spines, directed backwards, with the sides converging obliquely inwards; metathoracic paraptera concealed by the scutellum in dorsal view; propodeal spiracle orifices visible. Two strong acute spines on propodeum, longer than pronotal ones. First gastric tergite with a longitudinal ridge on each side; disk with two longitudinal series of small piligerous tubercles, absent in the middle of the segment.

Wings pale brown, completely covered by microtrichia. Fore wing with 5 closed cells (sub-median, median, costal, sub-marginal and marginal); anal vein turned up and fused with cubito-anal, not prolonged beyond the junction. Pterostigma conspicuous, although not pigmented. Hind wing with 5 complete veins, and 1 closed cell; 10 hamuli on anterior margin.

Male

Mayhe-Nunes and Brandão (2005) - TL 5.3-5.6; HL 0.83-0.95; HW 0.94-1.02; IFW 0.34-0.38; ScL 0.85-0.88; TrL 1.82-2.03; HfL 1.63-1.77; FWL 5.27-5.55; HWL 3.50-3.86. Dark brown, with antennae and legs ferruginous brown. Hairs moderately long and inclined, mixed with short and strongly curved hairs, conspicuous on head, dorsum of alitrunk and first segment of the gaster. Head. Mandibles finely striated on dorsal surface; masticatory margin with five teeth, gradually diminishing towards the base external margin s lightly sinuous. Median border of clypeus convex, with a large anterior notch; dorsal disk of clypeus without projections, but with one weak longitudinal carina on each side, between the base of frontal lobes and its anterior margin. Frontal lobes rounded and directed forwards, leaving part of the antennal insertions exposed. Frontal carinae subparallel, not reaching the occiput. Preocular carinae distinct, fading out at the posterior border of eyes. Compound eyes big and convex, filling some 1/2 of the head sides. Three prominent ocelli. Antennae with 13 segments; scape clearly surpassing the occipital corners, nearly three times longer than funicular segments I-III combined, with a basal lobe weakly projected; funicular segment I longer than II. Occipital corners rounded, with small spines and tubercles visible in frontal view. Occipital margin gently concave in the middle between the lateral ocelli.

Alitrunk: Pronotum with a scapular spine moderately long and acute. Scutum narrow with superficially impressed Mayrian furrows; parapsis shallowly impressed; parapsidial furrows conspicuously marked. Mesothoracic paraptera in dorsal view, slightly narrowed in the middle, where it is impressed and presents a series of short longitudinal keels, without side projections. Scutellum without dorsal projections, ending as two obsolete tubercles. Metathoracic paraptera backwards projected, partially visible in dorsal view. Propodeum with a pair of minute spines between basal and declivous faces.

Waist and gaster: Dorsum of petiole without projections. Postpeliole a little broader than petiole in dorsal view, superficially impressed above, with the posterior border concave. First gastric tergite without lateral ridges or piligerous tubercles, basally with a superficial impression on each side.

Wings similar as described for the female above; the unique noticeable difference is the 1Cu vein of the fore wing, much shorter in the male.

Type Material

Mayhe-Nunes and Brandão (2005) - Probably in the Royal Museum in Stockholm; not examined.

Karyotype

  • n = 10, 2n = 20, karyotype = 20M (Brazil) (Barros et al., 2018; Cardoso et al., 2018; Micolino et al., 2019; Micolino et al., 2020).

References

References based on Global Ant Biodiversity Informatics

  • Albuquerque E. Z., E. Diehl, and R. R. Silva. 2017. Structure of ground-dwelling ant communities in burned and unburned areas in Brazilian subtropical grasslands. Entomological Science 20: 427–436.
  • Camacho G. P., and H. L. Vasconcelos. 2015. Ants of the Panga Ecological Station, a Cerrado Reserve in Central Brazil. Sociobiology 62(2): 281-295.
  • 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.
  • Diehl-Fleig E. 2014. Termites and Ants from Rio Grande do Sul, Brazil. Sociobiology (in Press).
  • Fernández, F. and S. Sendoya. 2004. Lista de las hormigas neotropicales. Biota Colombiana Volume 5, Number 1.
  • Franco W., and R. M. Feitosa. 2018. First standardized inventory of ants (Hymenoptera: Formicidae) in the natural grasslands of Parana: New records for Southern Brazil. Pap. Avulsos Zool. 58: e20185812.
  • 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.
  • Mayhé-Nunes A. J., and C. R. F. Brandão. 2005. Revisionary studies on the attine ant genus Trachymyrmex Forel. Part 2: the Iheringi group (Hymenoptera: Formicidae). Sociobiology 45(2): 271-305.
  • 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.
  • 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.
  • 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.
  • Vasconcelos H. L., B. B. Araujo, A. J. Mayhé-Nunes. 2008. Patterns of diversity and abundance of fungus-growing ants (Formicidae: Attini) in areas of the Brazilian Cerrado. Revista Brasileira de Zoologia 25(3): 445-450.
  • Weber N. A. 1938. The biology of the fungus-growing ants. Part IV. Additional new forms. Part V. The Attini of Bolivia. Rev. Entomol. (Rio J.) 9: 154-206.
  • Wild, A. L. "A catalogue of the ants of Paraguay (Hymenoptera: Formicidae)." Zootaxa 1622 (2007): 1-55.