Acropyga sauteri

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Acropyga sauteri
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Formicinae
Tribe: Plagiolepidini
Genus: Acropyga
Species: A. sauteri
Binomial name
Acropyga sauteri
Forel, 1912

Acropyga sauteri casent0909907 p 1 high.jpg

Acropyga sauteri casent0909907 d 1 high.jpg

Specimen Labels

Evolutionary Relationships
Acropyga



Acropyga ayanganna




Acropyga donisthorpei



Acropyga panamensis







Acropyga guianensis



Acropyga stenotes






Acropyga fuhrmanni



Acropyga smithii





Acropyga romeo




Acropyga hirsutula




Acropyga dubitata




Acropyga decedens, Acropyga goeldii



Acropyga epedana












Acropyga arnoldi



Acropyga silvestrii






Acropyga kinomurai



Acropyga lauta





Acropyga sauteri




Acropyga acutiventris




Acropyga myops




Acropyga butteli




Acropyga ambigua



Acropyga pallida










Based on Blaimer et al., 2016. Note only selected Acropyga species are included, and undescribed species are excluded.

Lapolla (2004) - It has been found in grasslands and forests, under stones as well as in leaf litter and soil. It is a trophophoretic species, associated with the mealybug Eumyrmococcus smithii. Terayama (1988) reported that queens carried gravid mealybugs on their mating flights.

Identification

LaPolla (2004) - Worker: 11 segmented antennae; mesosomal dorsum flat with many short erect hairs; pronotum short, rises very steeply toward mesonotum; mandible with 3-4 teeth. Queen: As in worker with modifications expected for caste. Male: 12 segmented antennae; digiti 2.5 times longer than cuspi, with peg-like teeth along sides. Compare with Acropyga lauta.

The worker of this species is fairly easily recognized, with 3-4 teeth and no diastema separating the basal teeth from the other teeth. A. sauteri is currently placed in the myops species-group. The long digiti, similar shaped parameres and dark color of the male suggest a close relationship with Acropyga myops.

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Oriental Region: Taiwan (type locality).
Palaearctic Region: China, Japan.

From LaPolla (2004): This species has one of the most northerly distributions in the genus, ranging from Japan south to Macao in southern China.

Distribution based on AntMaps

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Distribution based on AntWeb specimens

Check data from AntWeb

Biology

Little is known about Acropyga sauteri. Until further studies reveal more about this species we can infer that its natural history and biology should be similar to other Acropyga. LaPolla published a worldwide revision of the Acropyga in 2004 and the following synopsis is based on this excellent treatment of the genus.

In overall appearance Acropyga are small, robust, yellowish ants possessing a thin, easily collapsible cuticle. The species generally appear rather similar to each other morphologically. In some species workers and queens display an unusual range of phenotypic variation. Antennal segment number, for example, can vary within and between species. Even a single specimen may posses antennae with a different number of antennal segments and workers in numerous species possess one more antennal segment than conspecific males.

The small eyes, reduced antennae segmentation, lightly pigmented cuticle, and hairs covering the cuticle of Acropyga species are suggestive of a completely subterranean existence. Species also display photophobic behavior (Weber, 1944; LaPolla et al., 2002). Acropyga can survive in a wide range of habitats, from deserts to rainforests, though they do not seem able to survive in regions where temperatures below freezing persist for several months at a time. Some species, such as Acropyga pallida and Acropyga silvestrii for example, are found within a very wide range of habitats. Undoubtedly, the Acropyga lifestyle of existing below the surface buffers them against extremes of the outside environment.

Acropyga nests are found in leaf litter, under stones, in rotten wood (lying on or near the soil surface) and in the soil. Observations of nests of various species show the nests are large, consisting of at least several thousand individuals. The nest structure is diffuse with apparently no central nesting location (LaPolla et al., 2002). Tunnels and indistinct chambers stretch out over large areas through the nesting medium. Polygyny has been suggested for several species. The origins of polygyny remains uncertain, but two routes are suggested based on field observations. Biinzli (1935) found both the occurrence of pleometrosis (founding of a colony by multiple queens) and the acquisition of young queens by established colonies in Acropyga exsanguis.

All Acropyga are thought to be hypogaeic (living entirely underground), surviving primarily by "tending" mealybugs (Hemiptera: Pseudococcidae) on underground roots for their exudate (sometimes referred to as "honeydew") (Weber, 1944; Williams, 1998). This mutually beneficial relationship is called trophobiosis (Holldobler and Wilson, 1990).

Acropyga species are all believed to be obligate coccidophiles (dependent on their tended mealybugs for survival). The strength of this trophophitic relationship is clarified by a number of observations. Queens of eleven species have been observed emerging from their nests prior to their mating flight with a mealybug held in their mandibles (Biinzli, 1935; Wheeler, 1935b; Brown, 1945; Eberhard, 1978; Prins, 1982; Buschinger et al., 1987; Williams, 1998; Johnson et al., 2001). The mealybug that each queen carries presumably serves as a "seed individual" from which a new generation of mealybugs will be started in the newly founded ant colony (Weber, 1944; Williams, 1998). This behavior is called trophophoresy (LaPolla et al. 2002) with queens exhibiting this behavior said to be trophophoretic. The mealybugs utilized by Acropyga belong to the subfamily Rhizoecinae, and it is likely that the mealybugs are not able to survive independently of the ants (Williams, 1998). LaPolla et al. (2002) observed that Acropyga epedana keeps mealybugs with their brood. When a nest in captivity was starved, workers refused a variety of food items presented to them, suggestiving that the ants are completely dependent on the mealybugs as a food source. Fossil evidence suggests that the trophobiotic behavior ofAcropyga ants is an ancient one. Johnson et al. (2001) reported that Acropyga queens were discovered in Dominican amber, either holding a mealybug or with a mealybug nearby in the amber matrix. The amber was dated to the Miocene and is at least 15-20 million years old.

Castes

Nomenclature

The following information is derived from Barry Bolton's New General Catalogue, a catalogue of the world's ants.

  • sauteri. Acropyga (Rhizomyrma) sauteri Forel, 1912a: 72 (w.) TAIWAN. Wheeler, W.M. 1928c: 31 (q.); Santschi, 1928b: 36 (q.m.). See also: Terayama, Fellowes & Zhou, 2002: 25; LaPolla, 2004a: 68.

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

Description

Worker

LaPolla (2004) - (n=2): TL: 2.16-2.59; HW: 0.527-0.568; HL: 0.561-0.596; SL: 0.413-0.418; ML: 0.681-0.687; GL: 0.909-1.31; CI: 101.25-105.2; SI: 66.67-72.71.

Head: yellow; head covered in layer of short appressed hairs; head about as broad as long; posterior margin slightly concave medially; short erect hairs along posterior margin; 11 segmented, incrassate antennae; scape reaches or slightly surpasses posterior margin; clypeus broad, slightly convex, with many erect hairs on dorsal surface; mandible with 3-4 teeth; apical tooth often much longer than others; when present, 4th tooth smaller and offset from masticatory margin; when with 3 teeth, a small hump present along inner mandibular margin where a 4th tooth would be; gap exists between inner mandibular margin and anterior clypeal margin. Mesosoma: yellow; in lateral view, pronotum with short shelf rising sharply toward mesonotum; pronotum covered with short erect hairs; mesosomal dorsum flat; mesonotum and propodeum at same height; mesonotum and propodeum covered in layer of short erect hairs; metanotal area indistinct; declivity steep. Gaster: petiole thick and erect reaching height of bottom portion of propodeal spriacle; gaster yellow, with thick covering of appressed hairs with scattered erect hairs throughout.

Queen

LaPolla (2004) - (n=1): TL: 3.39; HW: 0.732; HL: 0.619; SL: 0.495; ML: 1.19; GL: 1.58; CI: 118.26; SI: 67.62. As in worker with modifications expected for caste and the following differences: color a brownish-yellow, darker on apex of head, mesosomal and gaster dorsa.

Male

LaPolla (2004) - (n=1): TL: 2.21; HW: 0.5; HL: 0.452; SL: 0.371; ML: 0.819; GL: 0.941; CI: 110.62; SI: 74.2.

Head: yellow to dark brownish-yellow toward apex around 3 promient ocelli; head covered in a layer of short erect hairs; head broader than long; 12 segmented, slightly incrassate antennae; scape surpasses posterior margin by about 112 length of pedicel; clypeus broad, convex medially; mandible with 3-4 teeth; mandibular shape as in worker. Mesosoma: brownish-yellow; pronotum small and collar-like, overarched by mesonotum; dorsum flat with dense layer of short erect hairs; scutellum with longer erect hairs; propodeum long, slightly below level of mesonotum; declivity short and steep. Gaster: petiole thick and erect; gaster brownish yellow, covered in a layer of appressed hairs. Genitalia: in lateral view, parameres long and thin, tapering to rounded apices; cuspi short, nearly straight, with short peg-like teeth at rounded apices; digiti straight, much longer than cuspi (ca. 2.5 times), with short, peg-like teeth along sides toward truncated apices.

Type Material

LaPolla (2004) - Acropyga (Rhizomyrma) sauteri Forel, 1912a: 72 (w.). Syntype workers, TAIWAN: (no specific locality provided) (depository unknown) [not examined]. Wheeler, W.M., 1928: 31, description of queen; Santschi, 1928a: 36, description of queen and male; Terayama et ai., 2002: 25, description and key.

References

  • Forel, A. 1912b. H. Sauter's Formosa-Ausbeute. Formicidae (Hym.) (Schluss). Entomol. Mitt. 1: 67-81 (page 72, worker described)
  • LaPolla, J.S. 2004a. Acropyga of the world. Contributions of the American Entomological Institute. 33(3):1-130. PDF (page 68, fig. 28C, worker described)
  • Santschi, F. 1928b. Nouvelles fourmis de Chine et du Turkestan Russe. Bull. Ann. Soc. Entomol. Belg. 68: 31-46 (page 36, queen, male described)
  • Wheeler, W. M. 1928c. Ants collected by Professor F. Silvestri in China. Boll. Lab. Zool. Gen. Agrar. R. Sc. Super. Agric. 22: 3-38 (page 31, queen described)