Acropyga silvestrii

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Acropyga silvestrii
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Formicinae
Tribe: Plagiolepidini
Genus: Acropyga
Species: A. silvestrii
Binomial name
Acropyga silvestrii
Emery, 1915

Acropyga silvestrii casent0178254 profile 1.jpg

Acropyga silvestrii casent0178254 dorsal 1.jpg

Specimen labels

Even though the species is found in savanna type habitat in many places across its range, A. silvestrii apparently does not overlap with Acropyga arnoldi, which is found exclusively in southern Africa. (LaPolla 2004)


LaPolla (2004) - Worker: Antennae 11-10 segmented; head distinctly longer than broad; head width not greater than 0.5 mm; in lateral view pronotum with short shelf; mesosomal dorsum flat, with appressed hairs. Queen: unknown. Male: unknown. Compare with Acropyga arnoldi and Acropyga paleartica.

This species can be easily separated from Acropyga arnoldi by its size (A. silvestrii TL: 1.6-2.1; HW: 0.383-0.454 versus A. arnoldi TL: 2.1-2.4; HW: 0.517-0.619). Differentiation from Acropyga paleartica can be slightly more difficult, though the torulae of A. silvestrii are very closely set together (almost touching medially) and their mandibles do not have offset basal teeth.

The relationship of this species to A. arnoldi is unclear since males remain unknown. A. silvestrii is observed with up to 7 teeth, but has not been observed with at least a 4-segmented maxillary palp as in A. arnoldi and A. paleartica.

Keys including this Species


Latitudinal Distribution Pattern

Latitudinal Range: 0.355° to -8.22513°.

Tropical South

Distribution based on Regional Taxon Lists

Afrotropical Region: Eritrea, Ethiopia (type locality), Ghana, Kenya, Rwanda, Togo, Uganda, United Republic of Tanzania.

LaPolla (2004) - The distribution of A. silvestrii stretches from western Africa as far south and east as northern Tanzania. This is the only Acropyga known from the rainforests of Africa, which is interesting because in other areas where rainforests are found the diversity of Acropyga is substantially higher. The low species diversity found in Africa may be an artifact of collecting since there are few collections from Africa (particularly West Africa) available for study, or may indicate something of biological interest.

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.


The species is found in a variety of habitats from tropical savannas to rainforests; it has also been collected from cacao plantations. It has been recorded from elevations up to 1600 m.


Association with Other Organisms

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This species is a mutualist for the mealybug Williamsrhizoecus udzungwensis  (a trophobiont) in Tanzania (Schneider & LaPolla, 2020).


Known only from the worker caste.



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.


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

  • silvestrii. Acropyga silvestrii Emery, 1915g: 21, fig. 11 (w.) ERITREA.
    • Combination in Acropyga (Malacomyrma): Emery, 1922d: 109.
    • Status as species: Wheeler, W.M. 1922a: 928; Emery, 1925b: 30; Finzi, 1939a: 166; Bolton, 1995b: 58; LaPolla, 2004a: 78 (redescription); LaPolla & Fisher, 2005: 605 (in key); Hita Garcia, et al. 2013: 204; Madl, 2019: 13.

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



LaPolla (2004) - (n= 10): TL: 1.16-2.15; HW: 0.383-0.454; HL: 0.429-0.506; SL: 0.297- 0.349; ML: 0.425-0.567; GL: 0.64-1.16; CI: 84.0-95.18; SI: 72.12-82.2.

Head: yellow to slightly brownish yellow; covered in dense layer of appressed hairs; head distinctly longer than broad; posterior margin entire; 11-10 segmented, incrassate antennae; apical segment about as long as proceeding 3 segments; scape fails to reach posterior margin by about length of pedicel; clypeus medially slightly convex, with several erect hairs; mandible with 4-7 uneven teeth; inner mandibular margin nearly parallel with anterior clypeal margin. Mesosoma: yellow; pronotum in lateral with a short shelf, then rising steeply toward mesonotum; mesonotum flat, covered in layer of appressed to suberect hairs; metanotal area often distinct; propodeum at about same height as mesonotum, rounded toward a steep declivity. Gaster: petiole thick and erect, rounded at apex; gaster yellow; covered in a thick layer of appressed hairs, with suberect to erect hairs scattered throughout.

Type Material

LaPolla (2004) - Acropyga silvestrii Emery, 1915: 21. 5 syntype workers, ERITREA: Ghinda (Musee d'Histoire Naturelle Genève) [1 worker examined]. The designated lectotype is a worker labeled JSL TYPE # 125 and is deposited at MHNG.


  • Biinzli, G.H. 1935. Untersuchungen iiber coccidophile Ameisen aus den Kaffeefelden von Surinam. Mitteilungen der Schweizerischen Entomologischen Gesellschaft 16:455-593.
  • Brown, W.L., Jr. 1945. An unusual behavior pattern observed in a Szechuanese ant. Journal of the West China Border Research Society 15:185-186.
  • Buschinger, J., J. Heinze & K. Jessen. 1987. First European record of a queen ant carrying a mealybug during her mating flight. NatUlwissenschaften 74:139-140.
  • Cantone S. 2018. Winged Ants, The queen. Dichotomous key to genera of winged female ants in the World. The Wings of Ants: morphological and systematic relationships (self-published).
  • Eberhard, W.G. 1978. Mating swarms of a South American Acropygia [sic.] (Hymenoptera: Formicidae). Entomological News 89(1 & 2):14-16.
  • Eisner, T. 1957. A comparative morphological study of the proventriculus of ants (Hymenoptera: Formicidae). Bulletin ofthe Museum of Comparative Zoology 116:439-490.
  • Emery, C. 1915e. Formiche raccolte nell'Eritrea dal Prof. F. Silvestri. Boll. Lab. Zool. Gen. Agrar. R. Sc. Super. Agric. 10: 3-26 (page 21, fig. 11 worker described)
  • Emery, C. 1922c. Hymenoptera. Fam. Formicidae. Subfam. Myrmicinae. [part]. Genera Insectorum 174B: 95-206 (page 109, Combination in Acropyga (Malacomyrma))
  • Holldobler B . & E.O. Wilson. 1990. The Ants. Belknap Press, Cambridge, Massachusetts, 732 pp.
  • Johnson, c., D. Agosti, J.H. Delabie, K. Dumpert, OJ. Williams, M. von Tschimhaus & U. Maschwitz. 2001 . Acropyga and Azteca Ants with Scale Insects: 20 Million Years ofIntimate Symbiosis. American Museum Noviates 3335:1-18.
  • LaPolla, J.S. 2004a. Acropyga of the world. Contributions of the American Entomological Institute. 33(3):1-130. (page 78, fig. 32C, worker described)
  • LaPolla, J.S., S.P. Cover & U.G. Mueller. 2002. Natural history of the mealybug-tending ant Acropyga epedana, with descriptions of the male and queen castes. Transactions of the American Entomological Society 128(3):367-376.
  • Prins, AJ. 1982. Review of Anoplolepis with reference to male genitalia, and notes on Acropyga. Annals of the South African Museum 89:215-247.
  • Schneider, S.A., LaPolla, J.S. 2020. Trophobiosis between a new species of Williamsrhizoecus (Hemiptera: Coccomorpha: Rhizoecidae) and Acropyga silvestrii (Hymenoptera: Formicidae) in Tanzania. Zootaxa 4853, 283–291 (doi:10.11646/zootaxa.4853.2.9).
  • Weber, N.A. 1944. The Neotropical coccid-tending ants of the genus Acropyga Roger. Annals of the Entomological Society of America 37:89-122.
  • Wheeler, G.C. & J.C. Wheeler. 1953. The ant larvae of the subfamily Formicinae. Annals of the Entomological Society of America 46:126-171.
  • Wheeler, W. M. 1927h. Ants collected by Professor F. Silvestri in Indochina. Boll. Lab. Zool. Gen. Agrar. R. Sc. Super. Agric. 20: 83-106 (page 100, fig. 7 worker described)
  • Wheeler, W. M. 1935c. Myrmecological notes. Psyche (Camb.) 42: 68-72 (page 72, replacement name: indosinensis)
  • Wheeler, W.M. 1935b. Ants of the genus Acropyga Roger, with description of a new species. Journal of the New York Entomological Society 43:321-329.
  • Williams, D J . 1998. Mealybugs of the genera Eumyrmococcus Silvestri and Xenococcus Silvestri associated with the ant genus Acropyga Roger and a review of the subfamily (Hemiptera, Coccoidea, Pseudoccidae). Bulletin of the British Museum (Natural History)(Entomology) 67:1-64.

References based on Global Ant Biodiversity Informatics

  • Emery C. 1915. Formiche raccolte nell'Eritrea dal Prof. F. Silvestri. Bollettino del Laboratorio di Zoologia Generale e Agraria della Reale Scuola Superiore d'Agricoltura. Portici 10: 3-26.
  • Garcia F.H., Wiesel E. and Fischer G. 2013.The Ants of Kenya (Hymenoptera: Formicidae)—Faunal Overview, First Species Checklist, Bibliography, Accounts for All Genera, and Discussion on Taxonomy and Zoogeography. Journal of East African Natural History, 101(2): 127-222
  • LaPolla J.S. 2004. Acropyga (Hymenoptera: Formicidae) of the world. Contributions of the American Entomological Institute 33(3): 1-130.
  • Ross S. R. P. J., F. Hita Garcia, G. Fischer, and M. K. Peters. 2018. Selective logging intensity in an East African rain forest predicts reductions in ant diversity. Biotropica 1-11.
  • Wheeler W. M. 1922. Ants of the American Museum Congo expedition. A contribution to the myrmecology of Africa. VIII. A synonymic list of the ants of the Ethiopian region. Bulletin of the American Museum of Natural History 45: 711-1004