Cephalotes varians

Identification
De Andrade and Baroni Urbani (1999) - A member of the pallens clade characterised by the following apomorphies: in the worker propodeal sides unarmed or with a narrow membranaceous margin medially denticulate, in the soldier and in the gyne by the combination of head disc with foveae contiguous each other, in the soldier by the outer face of the hind femora superficially carinate, by the head longer than broad, and, in the gyne, by the petiole and postpetiole without or with reduced lateral expansions.

Distribution
This taxon was described from Cuba. It is also found in the United States, Dominican Republic, Bahamas and Trinidad and Tobago.

Biology
The nest sites ...are quite dry and it is likely that the large size of the eggs and the consumption and traffic in infrabuccal pellets are adaptations for water conservation. This species relies heavily on liquid food, with no feeding of solid food to the larvae other than infrabuccal pellets or trophic eggs. This reliance on liquid food in Z. varians is certainly associated with the fact that it is a scavenger. The reduced mandibles are associated with scavenging and the passive defense strategy (modified from Cole 1980).

Behavior
A remarkable three(!) ethograms have been published for this species.

Cole (1983) studied the behavioral repertoire of a mangrove ant community in southern Florida. Cephalotes varians ethogram 2. The focus of this work was to understand how worker behavior might influence colony growth and, in turn, how this might affect colonization ability. Some conclusions from this study about C. varians:

"colonies produce specialized castes that function in colony defence and little else (Cole 1980): Major workers are not produced during the early stages of colony founding (Wilson 1971). Thus during the period that the colony is at its most vulnerable, there is no defensive caste. By the criterion of caste structure, Z. varians and Colobopsis should have reduced colonizing ability compared to C. ashmeadi, X.floridanus or P. elongatus".....also...."The high queen-worker size ratio gives Z. varians an advantage in colonizing ability."

Wilson (1976) also examined and analyzed the behavioral repertoire of this species. An ethogram from this study is reproduced here Cephalotes varians ethogram 3 and the abstract nicely summarizes the findings and conclusions:

"An ethogram is presented of Zacryptocerus (=Cephaolotes)varians, a morphologically advanced member of the ‘turtle ants’ comprising the neotropical ant tribe Cephalotini. The species displays unusual and in one or two cases possibly even unique social behaviours, including the consumption and sharing of infrabuccal pellets, the apparent absence of adult transport, a primarily or exclusively mechanical form of colony defence, and a remarkable form of abdominal trophallaxis. All of these specializations seem to be associated with more primary adaptations by the species to arboreal nesting and scavenging. Among the additional results is the demonstration that the major worker is more specialized as a defensive caste than is the case in certain species of Camponotus and Pheidole."

Morphology
Wheeler and Holldobler (1985) investigated how Cepholates workers might collect or accumulate debri on their head disks. Such debri can be used as camouflage for individuals that are using their head to block the nest entrance, much like Basicerotini and Stegomyrmicini ant species affix dirt to their bodies. They discovered Cephalotes varians do in fact have encrusted material on their head disks. This varied from slight to extremely built-up material. Unexpectedly these covering materials appeared to be produced by the ants, rather than debri that was somehow affixed to the head disk. The presence of many pores, which are presumably attached to glands, are the likely source of secreted fibrous and filmy substances that were detected.

They also discovered: "Z. varians (Figs. 1-3). The heads of soldiers were covered with large, blade-like setae arched over large shallow pits. The sparse distribution of the pits gives the head a pock-marked appearance. The most remarkable feature of clean specimens was the high density of pores 1-3 # in diameter. These are almost certainly glandular openings (Fig. 1). The density of pores was about pore/350 #2, and the total number of pores on the disc was estimated to be over 8000 One specimen, which appeared only slightly grimy to the eye, was in fact covered with a dense tangle of material (Figs. 2, 3a) which resembled a mass of fungal filaments (mycelia). Patches of material on the head of a second specimen consisted of an encrusting layer as well as some filaments (Fig. 3b). Examination of the mat material under a light microscope revealed, however, none of the branching or internal structure indicative of a fungal origin. We suggest that the filaments are material extruded through what are apparently glandular openings."

Castes
Dimorphic - workers and soldiers.

Nomenclature

 *  varians. Cryptocerus varians Smith, F. 1876d: 606, pl. 11, fig. 6 (w.) CUBA. Wheeler, W.M. 1905b: 102 (s.q.m.); Wheeler, G.C. & Wheeler, J. 1954b: 156 (l.). Combination in Cryptocerus (Cyathocephalus): Emery, 1915i: 192; in Cryptocerus (Cyathomyrmex): Wheeler, W.M. 1937b: 459; in Paracryptocerus (Cyathomyrmex): Smith, M.R. 1951a: 825; in Zacryptocerus: Smith, D.R. 1979: 1403; in Cephalotes: De Andrade & Baroni Urbani, 1999: 457. See also: Wilson, 1976a: 354.

De Andrade and Baroni Urbani (1999) - Among the material of C. varians examined we observed the following variation: all the specimens from the Bahamas and those from Yateras (Cuba) have shorter peduncular spines. There seems to be no evident geographic pattern in the distribution of this character. The Bahamian specimens, in addition, may have the propodeal sides with a pair of teeth of variable size or simply marginate.

Worker
De Andrade and Baroni Urbani (1999) - Head slightly broader than long. Frons gently convex. Frontal carinae deeply incavate over the eyes and converging anteriorly. Vertexal angles with a pair of narrow, round or obtuse membranaceous expansions. Membranaceous expansions of the vertexal angles converging and not connected medially. Vertexal margin with a short "neck". Funicular club with two joints. Mandibles with superficial lateral carina.

Mesosoma. Scapular angles not visible in dorsal view. Anterior pronotal border convex. Pronotal sides with a pair of narrow, membranaceous expansions gently converging posteriorly. Promesonotal suture, in dorsal view, superficially impressed in some specimens only. Mesonotal sides with a pair of teeth truncate or pointed. Propodeum with poorly differentiate basal and declivous faces. Propodeal sides medially with a pair of triangular, membranaceous teeth of variable size; some specimens with the propodeal sides simply marginate or with a pair of narrow membranaceous expansions including the median teeth.

Petiole. Anterior face slightly concave. Petiolar sides with a pair of short, truncate or pointed teeth. Postpetiolar node convex dorsally; postpetiolar sides with a pair of spines, pointed or round and directed forwards.

Gaster. Oval and with a pair of anterolateral membranaceous expansions variably developed and not surpassing the stigma posteriorly.

Hind and mid femora gently angulate; their distal part with a dorsal longitudinal carina; the carina less impressed on the mid femora. Mid and hind basitarsi flat, with the proximal part broader than the distal one.

Sculpture. Head dorsum and mesosoma minutely reticulate and with superimposed superficial, dense foveae, shallower on the frontal carinae, sparser on the frons and denser on the mesosoma; some specimens with dense foveae on the whole head dorsum. Ventral part of the head reticulate and superimposed to foveae as on the frontal carinae on its anterior half. Pedicel minutely reticulate and with small, superficial foveae. Pleurae reticulate. First gastral tergite reticulate and with sparser, very superficial foveae, larger and more impressed on the anterior third. Gastral sternites and legs reticulate and with minute, superficial foveae, more impressed and denser on the outer face of the tibiae. Center of the first gastral sternite shining.

Pilosity. Each fovea with an appressed hair. Posterior half of the frontal carinae, vertexal angles, first gastral tergite and sternite, posterior border of the remaining gastral segments, and legs with rare clubbed hairs, slightly thinner on the first gastral sternite. Parts of the gaster and of the legs without foveae with short, appressed, very thin hairs. Gastral sternites with additional, rare, long, pointed hairs.

Colour. Ferruginous to brown with the frontal carinae and the membranaceous expansions of the body slightly lighter.

Measurements (in mm) and indices: TL 3.36-4.97; HL 0.82-1.16; HW 0.88-1.28; EL 0.19-0.26; PW 0.70-1.06; PeW 0.46-0.68; PpW 0.45-0.60; HBaL 0.27-0.36; HBaW 0.10-0.13; CI 107.3-118.5; PI 116.0-125.7; PPeI 138.2-216.7; PPpI 155.5-196.2; HBaI 34.3-38.7.

Soldier - Head disc suboval and covering completely the mandibles in dorsal view. Border of the disc strongly raised and with minutely crenulate margin, the crenulation more impressed on the posterior half. Floor of the disc medially with a small tumulus. Posterior part of the disc medially depressed. Vertexal angles completely separate from the disc, obtuse and with crenulate margin. Eyes slightly convex and hidden by the disc. Mandibles laterally carinate.

Mesosoma. Humeral angles with a pair of obtuse or slightly pointed teeth or with narrow membranaceous expansions. Pronotal sides gently converging posteriorly. Pronotal carina well marked, with crenulate margin and interrupted medially. Pronotal suture in dorsal view more impressed on the sides. Promesonotal suture deeply impressed. Mesonotal sides with a pair of broad, triangular teeth with almost round tip; some specimens with an additional pair of minute denticles. Propodeum with differentiate basal and declivous faces; sides of the basal face with two pairs of small, round swellings followed by a pair of stout teeth curved up and forwards in large specimens. Declivous face of the propodeum narrowing posteriorly.

Pedicel as in the worker but with narrower and shorter spines.

Hind femora dorsally gently angulate and with superficial carina in their distal part. Mid and hind basitarsi flat, with the proximal part broader than the distal one.

Gaster. Oval and with a pair of protruding lobes.

Sculpture. Head dorsum minutely punctate variably shining and with large, dense foveae, smaller on the tumulus and near the posterior border of the disc; foveae of the disc separated by thin interspaces. Sides of the head disc densely and irregularly foveolate, the foveae more superficial on the anterior half. Ventral part of the head punctate, variably shining; this sculpture covered by irregular, longitudinal rugosities on the posterior half and with small, dense, irregular foveae on the anterior half. Mesosoma minutely reticulate-punctate and with dense foveae, slightly irregular or oval on the pronotum, round on the mesonotum, small and superficial on the propodeum. Pedicel with similar sculpture as on the propodeum but with smaller foveae. Pleurae reticulate and with small, superficial foveae on the upper border. Gaster and legs with similar sculpture as in the worker but with slightly larger foveae.

Pilosity. Each fovea with an appressed or subdecumbent hair. Borders of the disc and sides of the head with many suberect, long, clavate hairs, sparser on the anterior border of the disc. Pronotum, first gastral segment, posterior border of the remaining gastral segments with rare, short clubbed hairs, denser on the first gastral sternite. Parts of the gaster and legs without foveae with short, appressed, thin hairs. Gastral sternites with additional rare, long, pointed hairs.

Colour. Dark ferruginous with slightly lighter gaster.

Measurements (in mm) and indices: TL 5.40-7.16; HL 1.44-1.96; HW 1.40-1.76; EL 0.30-0.33; PW 1.32-1.80; PeW 0.58-0.60; PpW 0.57-0.64; HBaL 0.32-0.39; HBaW 0.13-0.15; CI 84.8-97.2; PI 97.8-106.1; PPeI 227.6-305.1; PppI 231.6-300.0; HBaI 37.1-40.6.

Queen
De Andrade and Baroni Urbani (1999) - Differing from the soldier as listed below.

Sides of the disc with lower borders and with the margin more crenulate. Posterior part of the disc with deeper median depression.

Mesosoma. Humeral angles with a pair of triangular teeth with pointed or obtuse tip. Pronotal carina lower. Pronotum, mesonotum and scutellum flat in side view. Sides of the basal face of the propodeum anteriorly convex and posteriorly with a pair of teeth with round or pointed tip and slightly diverging backwards.

Wings figured in publication.

Petiole. Anterior face oblique and concave. Petiolar sides unarmed. Postpetiole as in the soldier but with the lateral spines broader, shorter and truncate.

Gaster. Similar to the one of the soldier but much longer.

Legs with less impressed carinae on the outer face of the femora.

Sculpture. Head dorsum with deeper, larger and denser foveae. Foveae on the mesonotum sparser. Pleurae reticulate. Propleurae with thin, faint, rugosities sometimes oriented transversally or longitudinally. Border of the lower metapleurae with thin, longitudinal rugosities. Upper part and center of the lower mesopleurae with small foveae, deeper and denser on the upper mesopleurae.

Pilosity. As in the soldier except for the clubbed hairs which are more abundant on the mesosoma and on the gaster.

Colour. Dark ferruginous.

Measurements (in mm) and indices: TL 7.52-8.36; HL 1.56-1.76; HW 1.44-1.58; EL 0.35-0.38; PW 1.32-1.56; PeW 0.51-0.56; PpW 0.57-0.64; HBaL 0.43-0.51; HBaW 0.15-0.17; CI 89.8-92.3; PI 101.3-109.1; PPeI 258.8-278.6; PPpI 231.6-243.7; HBaI 31.9-37.2.

Male
De Andrade and Baroni Urbani (1999) - Head (eyes included) more than 1/3 broader than long. Vertexal angles converging to the vertexal margin. Vertex dorsally protruding, bearing salient ocelli. Compound eyes broadly convex, at mid head length. Frontal carinae very short and with a raised, convex border.

Frons flat and with a median, superficial sulcus. Clypeus convex posteriorly and incised anteriorly. Mandibles short and superficially carinate on the sides. Scapes thick, twice as long as the first funicular joint; remaining funicular joints thickening from the base to the apex.

Mesosoma. Pronotum in dorsal view with the sides diverging backwards. Mesonotum convex in side view; median Mayrian furrow variably impressed but always present. Scutellum convex, rounded posteriorly. Basal and declivous faces of the propodeum differentiate; basal face gently convex dorsally and slightly declivous; declivous face with converging sides.

Petiole with concave anterior face; posterior face gently convex and sloping posteriorly. Petiolar sides converging backwards, with a minute pair of denticles or unarmed. Postpetiole convex; its sides with a small, round median denticle.

Gaster as broad as the mesosoma.

Genitalia and subgenital plate shown in publication figures.

Wings. As in the gyne.

Sculpture. Head dorsum reticulate and sparsely, irregularly rugose, some specimens only; this structure superimposed to few, superficial, foveae more regular and denser behind the pair ocelli. Ventral part of the head reticulate, irregularly rugose-foveolate. Pronotum, mesonotum and scutellum with superficial, minute reticulation and with foveae as on the posterior part of the head dorsum, the foveae shallower and sparser on the mesonotum and scutellum. Basal face of the propodeum reticulate and with generally irregular, longitudinal rugosities. Declivous face of the propodeum, pedicel and propleurae reticulate. Mesopleurae reticulate; center of the lower and upper mesopleurae superficially foveolate; lower mesopleurae with few additional, longitudinal rugosities. Metapleurae reticulate and with irregular rugosities on the upper part. Gaster superficially reticulate and subopaque to shining. Legs punctate with moderately shining femora.

Pilosity. Body with long, thin, flexuous, pointed, golden hairs, dense on the head, on the mesosoma and on the pedicel, sparser on the gaster and on the femora. Gaster and legs with similar hairs but shorter, appressed on the tergites, decumbent on the sternites and on the femora. Tibiae and tarsi with short, pointed hairs.

Colour. Dark ferruginous-brown with slightly lighter coxae, pedicel and gaster. Legs yellowish with darker tarsomeres.

Measurements (in mm) and indices: TL 4.39-5.20; HL 0.70-0.75; HW 0.84-0.92; EL 0.30-0.41; PW 0.75-0.84; PeW 0.33-0.40; PpW 0.35-0.45; HBaL 0.44-0.47; HBaW 0.07-0.08; CI 120.0-122.7; PI 109.5-112.0; PPeI 210.0-227.3; PPpI 186.7-214.3; HBaI 14.9-18.2.

Type Material
De Andrade and Baroni Urbani (1999) - Type locality: Cuba. Type material 4 syntype workers on the same pin labelled "from Cuba, varians, Sm. Type (Cuba)" in, examined.

Additional References

 * Cole, B. J. 1980. Repertoire convergence in two mangrove ants, Zacryptocerus varians and Camponotus (Colobopsis) sp. Insect. Soc. 27:265-275.


 * Cole, B. J. 1983. Assembly of mangrove ant communities: colonization abilities. Journal of Animal Ecology 52:349-355.


 * [[Media:Wheeler_&_Holldobler_1985.pdf|Wheeler, D. E.; Hölldobler, B. 1986 ("1985"). Cryptic phragmosis: the structural modifications. Psyche (Cambridge) 92:337-353. [1986-04-27] PDF]] DOI:10.1155/1985/76848


 * Wilson E.O. 1976. A social ethogram of the neotropical arboreal ant, Zacryptocerus varians (Fr. Smith). Animal Behavior. 24:354-363. DOI [10.1016/S0003-3472(76)80043-7]