Anoplolepis custodiens

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Anoplolepis custodiens
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Formicinae
Tribe: Plagiolepidini
Genus: Anoplolepis
Species: A. custodiens
Binomial name
Anoplolepis custodiens
(Smith, F., 1858)

Anoplolepis custodiens casent0170537 profile 1.jpg

Anoplolepis custodiens casent0170537 dorsal 1.jpg

Specimen Label

Subspecies
Synonyms

One of a few species of common, abundant Anoplolepis species in southern Africa that are well known - as pugnacious ants - to people living in areas where these ants occur. Anoplolepis custodiens are agressive, fast moving ants. When sensing anything that can be perceived as a threat workers will swarm and attack. Honeydew is part of their diet and Anoplolepis custodiens tending of honeydew producing pest species can lead to these ants causing problems in some agricultural settings.

Identification

Prins (1982) - The chequered pattern on abdomen and form of the clypeus are not as distinct as in the majors or media and this caste is therefore difficult to identify in the absence of larger workers. The convex epinotum is characteristic of the workers of the subgenus Zealleyella, and seen from the side it is almost as high as the promesonotum in the majors; in the minors it may be much higher.

Distribution

Distribution based on Regional Taxon Lists

Afrotropical Region: Botswana, Kenya, Lesotho, Mozambique, Namibia, South Africa (type locality), Swaziland, United Republic of Tanzania, Zimbabwe.

Distribution based on AntMaps

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Distribution based on AntWeb specimens

Check data from AntWeb

Biology

As an aggressive and voracious predator species Anoplolepis custodiens prey on many different organisms. A study examining how group living by social spiders may increase their risk of discovery and death by predatory ants (Keiser et al. 2015) found colonies of Stegodyphus dumicola were attacked and eliminated by A. custodiens.

This species has been found attached by its mandibles to the leg of a species of Pausus.

Castes

Nomenclature

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

  • custodiens. Formica custodiens Smith, F. 1858b: 33 (w.) SOUTH AFRICA. Mayr, 1895: 148 (m.); Emery, 1895h: 44 (q.); Wheeler, G.C. & Wheeler, J. 1953c: 135 (l.). Combination in Plagiolepis: Emery, 1892a: 117; in Plagiolepis (Anoplolepis): Santschi, 1914b: 123; in Plagiolepis (Zealleyella): Arnold, 1922: 586; in Anoplolepis: Emery, 1925b: 17. Senior synonym of hendecarthrus: Mayr, 1865: 54; of berthoudi: Forel, 1879a: 91. See also: Prins, 1982: 218. Current subspecies: nominal plus detrita, hirsuta, pilipes.
  • hendecarthrus. Camponotus hendecarthrus Roger, 1863a: 132 (w.q.) SOUTH AFRICA. Junior synonym of custodiens: Mayr, 1865: 54.
  • berthoudi. Formica berthoudi Forel, 1876: 33 (w.) LESOTHO. Junior synonym of custodiens: Forel, 1879a: 91.

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

Description

Worker

Length 2 lines. Head, thorax and legs ferruginous, and covered with a silky cinereous pile. Head emarginate behind. The thorax deeply strangulated at the base of the metathorax; the scale of the peduncle narrow, incrassate, obtuse above. Abdomen ovate, black, and covered with grey silky pile.

Prins (1982) - TL 3-10 mm; L 2,0-5,0 mm; HL 0,76-2,2 mm; ED 0,48-1,64 mm; CL 0,24-0,80 mm; SL 0,96-2,44 mm; WL 1,08-3,30 mm; MFL 0,80-2,56 mm; HFL 1,02-3,0 mm; PL 0,16-0,40 mm; CI 94,7-104,5; SI 133,3-106,1; CLI 200,0; CTI 70,4-66,7; TI 44,4--44,8; PI 125,0-190; HFI 94,4-90,9.

Polymorphic, colour yellowish-brown to reddish-brown or even somewhat darker with abdomen dark-brown to almost blackish-brown, therefore easily confused with workers of the black pugnacious ant. Separated from latter species by chequered pattern on abdomen, caused by reflection of light on pubescent hairs, which are arranged in two different directions on each side. Few pilose hairs also present, particularly on head, apical borders of abdominal segments and on femora.

Anterior border of cypeus angular in the middle, acutely so in some specimens; in lateral view less convex than in black pugnacious ant. Scale of petiole rather flattened in larger workers and fairly deeply emarginate above; scale narrowed dorsally in minors and emargination generally almost obsolete.

Queen

Prins (1982) - Wing-span about 27,4 mm; TL 13,3-15,8 mm; L 6,5-7,3 mm; HL 2,2 mm; ED 1,9 mm; CL 0,7 mm; SL 2,3 mm; WL 4,5-5,2 mm; MFL 2,4-2,6 mm; HFL 2,8-2,9 mm; PL 0,44-0,48 mm; CI 113,6; SI 92,0; CLI 242,8-257,2; CTI 48,9-42,3; TI 68,9-67,3; PI 216,7-241,7; HFI 62,2-55,6.

It has the general features of the females of the subfamily Formicinae, with a distinct chequered pattern on the abdomen and a wide and fairly deep emargination on the dorsal edge of the scale of the petiole. Colour more or less as in the worker, the wings ochreous-yellow with darker subcostal cell; the abdomen sometimes much darker. Clypeus also angular in the middle as in the case of the workers.

Wing venation as in Figures 3A, 4A, and although there are minor variations in the venation of the same individual, the vein m + cua of the hind wing much shorter than the preceding cell Ia; in the specimens examined, this vein is shorter than half the length of the cell.

Male

Prins (1982) - Wing-span about 19,0 mm; TL 9,9-10,8 mm; L 3,6-3,7 mm; HL 1,6-1,64 mm; ED 1,2 mm; CL 0,44-0,48 mm; SL 2,2 mm; WL 3,5-3,8 mm; MFL 2,5-2,7 mm; HFL 2,8-3,0 mm; PL 0,4 mm; CI 112,5-109,8; SI 12,2; CLI 254,5-233,3; cn 45,7-40,3; n 57,9-62,9; PI 190-200; HFI 80,0-78,9.

Slightly smaller than the female and, as in the case of the latter, they resemble the males of the subfamily Formicinae. Indistinct chequered pattern present on the abdomen, although the direction in which the pubescent hairs are arranged is fairly clearly indicated. Generally darker in colour than female, more slender, and the clypeus also angular in the middle. Scale of petiole with indistinct emargination on dorsal edge. Labrum as in Figure. Although the vein m + cua of the hind wing is much longer in most specimens seen, it is not longer than half the length of cell la.

External male reproductive organs

The last complete visible segment in the abdomen of the male is the sixth (the true eighth), the seventh (true ninth) being reduced to a ring-like sclerite (also known as gonocardo or lamina annularis), which is membraneous dorsally, but on the ventral side it is flattened, plate-like and sclerotized. In A. custodiens the flattened plate is fairly deeply and angularly emarginate behind. The two lobes formed by the emargination are thinner than the rest of the plate and are ventrally covered with fine hairs. The plate itself is about twice as wide as long. Penis or aedeagus situated medially and characterized by its two lobes; it is somewhat shorter than external lobes, which cover reproductive organs and are also known as gonostipes (gonoforceps or parameres). In lateral view the apices of go no stipes are round and broad. On each side and somewhat below penis is a globular volsella with an outer appendage or cuspis and an inner shorter digitus. Both digiti and cuspides are devoid of denticles, except in case of some individuals where there are a few tubercles, particularly on apices of cuspides. Each volsella has some fine hairs on ventral side.

References

  • Arnold, G. 1922. A monograph of the Formicidae of South Africa. Part V. Myrmicinae. Ann. S. Afr. Mus. 14: 579-674 (page 586, combination in Plagiolepis (Zealleyella))
  • Emery, C. 1892b. Sopra alcune formiche raccolte dall'Ingegnere L. Bricchetti Robecchi nel paese dei Somali. [concl.]. Ann. Mus. Civ. Stor. Nat. 32[=(2(12): 113-122 (page 117, combination in Plagiolepis)
  • Emery, C. 1895i. Voyage de M. E. Simon dans l'Afrique australe (janvier-avril 1893). 3e mémoire. Formicides. Ann. Soc. Entomol. Fr. 64: 15-56 (page 44, queen described)
  • Emery, C. 1925d. Hymenoptera. Fam. Formicidae. Subfam. Formicinae. Genera Insectorum 183: 1-302 (page 17, combination in Anoplolepis)
  • Forel, A. 1879a. Études myrmécologiques en 1879 (deuxième partie [1re partie en 1878]). Bull. Soc. Vaudoise Sci. Nat. 16: 53-128 (page 91, senior synonym of berthoudi)
  • Keiser, C. N., C. M. Wright, and J. N. Pruitt. 2015. Warring arthropod societies: Social spider colonies can delay annihilation by predatory ants via reduced apparency and increased group size. Behavioural Processes. 119:14-21. doi:10.1016/j.beproc.2015.07.005
  • 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 54, senior synonym of hendecarthrus)
  • Mayr, G. 1895. Afrikanische Formiciden. Ann. K-K. Naturhist. Mus. Wien 10: 124-154 (page 148, male described)
  • Prins, A. J. 1982. Review of Anoplolepis with reference to male genitalia, and notes on Acropyga (Hymenoptera, Formicidae). Ann. S. Afr. Mus. 89: 215-247 (page 218, see also)
  • Santschi, F. 1914b. Voyage de Ch. Alluaud et R. Jeannel en Afrique Orientale, 1911-1912. Résultats scientifiques. Insectes Hyménoptères. II. Formicidae. Paris: Libr. A. Schulz, pp. 41-148. (page 123, combination in Plagiolepis (Anoplolepis))
  • Smith, F. 1858a. Catalogue of hymenopterous insects in the collection of the British Museum. Part VI. Formicidae. London: British Museum, 216 pp. (page 33, worker described)
  • Wheeler, G. C.; Wheeler, J. 1953c. The ant larvae of the subfamily Formicinae. Ann. Entomol. Soc. Am. 46: 126-171 (page 135, larva described)