Mycetophylax auritus

Mycetophylax auritus
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Hymenoptera
Family:	Formicidae
Subfamily:	Myrmicinae
Tribe:	Attini
Genus:	Mycetophylax
Species:	M. auritus
Binomial name
Mycetophylax auritus (Mayr, 1887) Specimen Labels

Preferentially nests in rotten wood in an advanced state of decay.

Identification

Kempf (1964) - Mycetophylax auritus is a highly distinctive species and its closest relative is Mycetophylax strigatus, a smaller sympatric form, from which it is however easily separated by the characters given in the key.

Distribution

Latitudinal Distribution Pattern

Latitudinal Range: -23.366667° to -23.7475°.

North Temperate	North Subtropical	Tropical	South Subtropical	South Temperate

• Source: AntMaps

Distribution based on Regional Taxon Lists

Neotropical Region: Brazil (type locality).

Distribution based on AntMaps

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.

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.

Biology

Expand 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. some Crematogaster some Lasius 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. some Apterostigma Cyatta (1 species) some Cyphomyrmex Kalathomyrmex (1 species) Mycocepurus (6 species) Myrmicocrypta (31 species) Mycetarotes (4 species) Mycetosoritis (2 species) Mycetophylax (21 species) Paramycetophylax (1 species) Xerolitor (1 species) Coral Fungus Agriculture Practiced by species in the Apterostigma pilosum species-group, which cultivate fungi within the Pterulaceae. some Apterostigma 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. some Cyphomyrmex 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. Mycetomoellerius (33 species) Paratrachymyrmex (9 species) Sericomyrmex (11 species) Trachymyrmex (9 species) 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. Acromyrmex (51 species) Amoimyrmex (3 species) Atta (20 species) 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. ‎

Kempf (1964): Moeller (1893) found this species to be rather common in the environs of Blumenau, where he performed his pioneering studies on the fungus culture of Attine ants. Excluding strays, he detected about 50 colonies of auritus and Mycetophylax strigatus, the exact number for each species is not given. Nests are preferably established in rotten wood in advanced state of decay. Cavities are generally small, usually not measuring more than 8 cc in volume. One nest, under the bark of a decaying log, was flat, measuring 15 by 15 cm. Like most small Attini, C. auritus workers were feigning death upon being disturbed, but recovered more speedily from the cataleptic state than Apterostigma workers. The fungus garden consisted of a regular sponge-like mass similar to that of Apterostigma pilosum and Apterostigma moelleri, built upon the floor of the nest. The substrate consisted mainly of insect feces. In artificial nests the ants accepted eagerly saw-dust and manioc flour as substrate. Although the specific identity of the fungus is not known, it seems to be a basidiomycete. The gongylidia of the fungus cultivated by auritus are irregular in shape and thickness (cf. Moeller, pl. 7, fig. 25), different from those obtained in the culture of strigatus nests. In captivity both species accepted and ate each others' fungus, rejecting however that of Apterostigma and Acromyrmex.

The colony discovered by Spitz in the vicinity of Alto da Serra, São Paulo State, consisted of approximately 30 workers and 1 dealate queen. The nest was in a decaying log in the forest. The substrate consisted of small vegetable debris, which gave the alcohol, in which it was preserved, a greenish color. The colony encountered by Lenko at Boracéia was also in a decaying log, facing another log, and numbered 32 workers and 1 female.

Luederwaldt's (1926) observations agree essentially with the preceding data. He found a nest of auritus, containing approximately 60 workers between epiphytic roots, in an artificially enlarged cavity. The fungus garden was subglobular, having half the size of a chicken's egg. Upon opening the nest, the ants fell into the well-known cataleptic state.

Nomenclature

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

• auritus. Cyphomyrmex auritus Mayr, 1887: 559 (w.q.m.) BRAZIL.
  • Combination in Mycetophylax: Sosa-Calvo et al., 2017: 9.
  • See also: Kempf, 1964d: 9.

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

Description

Worker

Kempf (1964): Total length 4.1-4.8 mm; head length 1.01-1.25 mm; head width 0.85-0.99 mm; thorax length 1.28-1.47 mm; hind femur length 1.20-1.47 mm. Yellowish brown to dark reddish brown. Integument densely granular, opaque, including antennal scrobe.

Head as shown in Fig. 1. Mandibles with 8-9 teeth. Clypeus: anterior border mesially excised, middle portion obliquely raised towards front, with two prominent teeth next to origin of frontal lobes. Two pairs of longitudinal carinae on dorsum of head, one in front, following the impressed frontal area, the other more widely spaced on vertex. Supraocular tooth conical and prominent, with a subcarinate ridge arising from its base and extending obliquely backwards to the inferior occipital angle on sides of head. Inferior or outer border of antennal scrobe only vestigially carinate between eyes and occipital lobes. The latter auriculate or horn-like, each considerably longer than its maximum width. Lower border of sides of head carinate. Antennal scape in repose not projecting beyond tip of occipital lobe. All funicular segments distinctly longer than broad.

Thorax as shown in Fig. 13. Pronotum: anterior and lateral border of dorsal face marginate to carinate; a single low conical median tubercle on disc; lateral tubercles low, tooth-like; antero-inferior corner with a small, subacute tooth. Mesonotum: 2 pairs of long conical teeth, the anterior pair longest. A broad and deep impression between the posterior mesonotal tooth and the anterior end of the paired longitudinal carinae of basal face of epinotum, which terminate posteriorly in a small tooth. Legs slender and long; femora lacking carinate ventral edges; hind femora not conspicuously dilated nor ventrally angulate on basal third.

Pedicel as shown in Figs. 13 and 25. Petiole, in dorsal view, with a quadrate node, anterior corners angulate, dorsum with a pair of short, tooth-like ridges. Postpetiole usually not broader than long, its sides subparallel; in profile, perpendicularly raised in front below the prominent, paired, anterior tubercles, connected with the paired posterior tubercles by subparallel longitudinal blunt ridges; space between ridges excavate, more deeply so on posterior half. First tergum of gaster with a pair of median and another pair of lateral sharp longitudinal carinae, the median pair often tuberculate near its anterior end.

Hairs appressed, scarce, minute, fine, not scalelike, slightly more conspicuous along ridges, on spines and on tubercles; still more prominent on scapes and legs.

• 

  Figs. 13-24

• 

  Figs. 25-36

Queen

Kempf (1964): Total length 5.4 mm; head length 1.20 mm; head width across supraocular spine 0.99 mm; thorax length 1.65 mm; hind femur length 1.60 mm. Very much like the worker, with the differences of the caste. Head exactly as in worker, with the same prominent occipital lobes. Anterior half of middle portion of clypeus perpendicular to posterior half, wedged in between frontal carinae, both faces forming at their junction a marked emarginate edge between the lateral clypeal teeth. Lateral ocelli situated on the outer face of the paired ridges of vertex. Pronotum with a single median tubercle, and a lateral tooth on each side, the latter connected with the anterior border by a low but marked carina, separating the dorsum from the sides of pronotum; antero-inferior tooth acute and prominent. Scutum with a broad and deeply impressed Y-like furrow, the area between the arms of the Y raised, laterally marginate, mesially excavate; lateral areas forming a blunt and raised tuberosity mesad along stem of Y-shaped furrow, being excavate laterad, with a deeply impressed pit near border forming a prominent, upturned ridge. Scutellum antero-mesially impressed, paraptera with a prominent tubercle; postero-mesial portion of scutellum bidentate, with a low; blunt tubercle preceding each tooth. Epinotal spines subtriangular, blunt at apex, prominent. Legs as in worker, but femora ventrally faintly marginate yet not incrassate at basal third, not forming an angle on flexor face. Petiole as in worker, but postpetiole is decidedly transverse, i. e. the sides are conspicuously diverging caudad, the anterior tubercles are slightly lower and the posterior tubercles are more widely separate. Gaster with the two pairs of longitudinal sharp carinae as in worker.

According to Mayr's description, the female lacks a median pronotal tubercle. The two queens observed by myself have a rather well-developed median tubercle, as stated in the description. Perhaps this is a variable feature.

Type Material

Kempf (1964) - In the Mayr collection at the "Naturhistorisches Museum", Vienna, Austria; not seen. A single worker, from Santa Catarina State, formerly belonging to the H. v. Jhering collection (now DZSP), is probably a syntype of Mayr's original series, as suggested by the peculiar type of mounting.

References

• Kempf, W. W. 1964d. A revision of the Neotropical fungus-growing ants of the genus Cyphomyrmex Mayr. Part I: Group of strigatus Mayr (Hym., Formicidae). Stud. Entomol. 7: 1-44 (page 9, see also)
• Luederwaldt, H. 1926. Observações biologicas sobre formigas brasileiras especialmente do estado de São Paulo. Rev. Mus. Paul. 14:185-303.
• Mayr, G. 1887. Südamerikanische Formiciden. Verh. K-K. Zool.-Bot. Ges. Wien 37: 511-632 (page 559, worker, queen, male described)
• Moeller, A. 1941. As hortas de fungo de algumas formigas sulamericanas. Rev. Entomol. (Rio de Janeiro). 1 (Supplemento):1-120.
• Sosa-Calvo, J., JesÏovnik, A., Vasconcelos, H.L., Bacci, M. Jr., Schultz, T.R. 2017. Rediscovery of the enigmatic fungus-farming ant "Mycetosoritis" asper Mayr (Hymenoptera: Formicidae): Implications for taxonomy, phylogeny, and the evolution of agriculture in ants. PLoS ONE 12: e0176498 (DOI 10.1371/journal.pone.0176498).