Anoplolepis custodiens

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 based on Regional Taxon Lists
Afrotropical Region: Botswana, Kenya, Lesotho, Mozambique, Namibia, South Africa, Swaziland, United Republic of Tanzania, Zimbabwe.

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.

Nomenclature

 *  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.

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.