Dolichoderus coniger

Dolichoderus coniger, a herdsmen species, is associated with several mealybug species from the genus Malaicoccus (proved for Poring [Sabah]: M. poringensis, Long Pala [E-Sarawak]: M. easropi, and Kubah NP [W-Sarawak]: M. kubahensis). These are transported by coniger on a regular basis. The observed long trails with high activity indicate a large colony size. The population from Kubah showed a peculiar defense behaviour that differed from all other observed Dolichoderus: for defense the ants smear a sticky, yellowish white fluid released from the gaster. (Dill 2002)

Identification
Dill (2002) - A member of the Dolichoderus cuspidatus species group. Mainly characterized by the presence of one pair of well developed, slender spines on the propodeum that are very similar to those found in Dolichoderus cuspidatus. Further, the surface sculpturing, the shape of the head and of the petioiar scale are very close to cuspidatus. In contrast to cuspidatus, the mesonotum of coniger is not armed with spines, although its hump is distinctly higher than in the other unarmed species. With regard to the spine development, coniger seems to occupy an intermediate position between Dolichoderus brevithorax, Dolichoderus cuspidatus, and Dolichoderus furcifer on one side, and the species without spines on the other side. In this respect coniger is similar to Dolichoderus magnipastor, although coniger distinctly differs in several characters, such as sculpturing (coniger lacks the coarse areolate wrinkles), width of the head (CI smaller in coniger), and the length and inclination of the spines (spines in magnipastor distinctly projecting over sides of propodeum).

Mayr, in his original description, describes the entire body surface as bald. In fact, even some specimens of Mayr’s syntype series bear, although sparsely developed, a fine pubescence on some gaster tergites. Unfortunately, apart from “Sarawak”, no further details on the collecting location are given for the type series. The other material from Sarawak (Multi NP, Kubah NP) and Sabah (Poring, Danum Valley) differ in several characters from the types. For instance, the pubescence, particularly on gaster tergites is usually very dense, although larger bald spots occur in certain specimens. The angle formed by the dorsal face of the propodeum is more pronounced in the Poring material than in the other examined series. Also, the outline of the mesonotum may vary considerably. For instance, in the material from Banlu Rure and East Sarawak (Mulu NP) it is lower and more pointed than in the type series and the Poring material. The lack of clinal transitions in these differences may be caused by the low number of available series.

Distribution
Dill (2002) - Borneo: Sabah and Sarawak. The distributional restriction of the available material to the northern part of Borneo is most probably caused by the very low number of ant collections from Kalimantan.

Distribution based on Regional Taxon Lists
Indo-Australian Region: Borneo, Indonesia, Malaysia.

Nomenclature

 *  coniger. Hypoclinea conigera Mayr, 1870b: 956 (diagnosis in key) (w.) BORNEO. Combination in Dolichoderus: Emery, 1887a: 256; in D. (Hypoclinea): Emery, 1894c: 229; in D. (Diabolus): Wheeler, W.M. 1935c: 68. See also: Dill, 2002: 33.

Worker
Dill (2002) - (Syntype of NHMW in brackets): HL 1.27-1.76 [1.57]; HW 1.28-1.86 [1.63]; EL 0.26-0.33 [0.31]; SL 1.18-1.44 [1.31]; AL 1.88-2.54 [2.22]; PnW 0.82-1.18 [1.04]; ML 0.57-0.73 [0.67]; MW 0.35-0.49 [0.43]; MH 0.16-0.40 [0.31]; PpL 0.73-1.04 [0.80]; PpW 0.67-0.90 [0.76]; PpH 0.90-1.56 [0.98]; PpSW 0.47-0.86 [0.65]; PtW 0.40-0.65 [0.58]; TL 5.18-6.80 [6.14]. Indices: CI 95-106 [104]; OI 18-21 [19]; SI 77-98 [81]; MI 141-177 [155]; PpSPpI 71-96 [85]; (n = 32).

Head: From yellowish-, reddish- or blackish-brown to black. Finely reticulate (= micro-imbricate) (fig. III-57b), slightly shining. Often, in addition to the tine sculpturing, with shallow, oval to subcircular depressions (each of them with one pubescence hair, if present); occasionally with fine, irregular, parallel lineation on vertex and frons. Apart from scapus and funiculus, pubescence almost absent (type series) or sparse; always void of pilosity. Occasionally with shallow median sliperoccipital pit (lacking in type series) and shallow lateral depressions near the posterior margin of head (fig. III -57a). Head roundly heart-shaped, posterior margin ± distinctly concavely emarginate; eyes relatively small (see OI).

Alitrunk: From yellowish-, reddish- or blackish-brown to black. Pronotum, sides of propodeum and legs very finely reticulate (= micro-imbricate), slightly shining. Mesopleuron, mesonotum and dorsal face of propodeum in addition with coarser, irregular to reticulate wrinkles. Dorsal face of alitrunk bald (syntypes) or sparsely pubescent; only a few single erect hairs on ventral side and coxae. Dorsal face of pronotum flat to slightly convex in profile, its lateral delimination not distinct; anterior “shoulder” corners rounded but distinctly developed. Mesonotum bearing a single, relatively steep and high cone-shaped hump, the tip of which is blunt or ± pointed in profile, with (type) or without a median depression on top. Posterior margin of mesonotum often indistinct. Processes of anterior margin of mesopleuron only weakly developed (rather low, triangular protuberances than cone-shaped). Dorsal face of propodeum, in profile, in its anterior portion only slightly ascending; then sharply, almost vertically bending upwards. Its corner expanded to a pair of spines that are slightly bended back and sideward, their tips pointed (syntypes) or spatulately broadened, sometimes with additional minute spikes pointing backward. In dorsal view, spines not projecting over the sides of the propodeum. Bulla of metapleural gland distended, smooth and shiny.

Petiolus: From reddish- to dark-brown to black. Very finely reticulate-punctate (= micro-imbricate). Dorsal margin of scale emarginate, sparsely pubescent.

Gaster: Reddish- to dark-brown or black. Very finely reticulate-punctate (= micro-imbricate); shiny. Tergites sparsely (types) or densely covered with fine, bright yellow pubescence; only sparse erect hairs on sternites and gaster tip.

Type Material
Dill (2002) - Syntype workers, Borneo [locality not specified] (Doria) [examined].

References based on Global Ant Biodiversity Informatics

 * Chapman, J. W., and Capco, S. R. 1951. Check list of the ants (Hymenoptera: Formicidae) of Asia. Monogr. Inst. Sci. Technol. Manila 1: 1-327
 * Dill M. 2002. Taxonomy of the migrating herdsmen species of the genus Dolichoderus Lund, 1831, with remarks on the systematics of other southeast-Asian Dolichoderus. Pp. 17-113 in: Dill, M.; Williams, D. J.; Maschwitz, U. 2002. Herdsmen ants and their mealybug partners. Abhandlungen der Senckenbergischen Naturforschenden Gesellschaft 557: 1-373.
 * Dill M., D.J. Williams, and U. Maschwitz. 2002. Herdsmen ants and their mealybug partners. Abh. senckenberg. naturforsch. Ges. 557: 1-373.
 * Emery C. 1887. Catalogo delle formiche esistenti nelle collezioni del Museo Civico di Genova. Parte terza. Formiche della regione Indo-Malese e dell'Australia. [part]. Ann. Mus. Civ. Stor. Nat. 24(4): 209-258.
 * Emery C. 1913. Hymenoptera. Fam. Formicidae. Subfam. Dolichoderinae. Genera Insectorum 137: 1-50.
 * Emery, C.. "Catalogo delle formiche esistenti nelle collezioni del Museo Civico di Genova. Parte terza. Formiche della regione Indo-Malese e dell'Australia." Annali del Museo Civico di Storia Naturale Giacomo Doria (Genova) (2) 4, no. 24 (1887): 209-258.
 * Johnson C., D. Agosti, J. H. C. Delabie, K. Dumpert, D. J. Williams, and M. Tschirnaus. 2001. Acropyga and Azteca ants (Hymenoptera: Formicidae) with scale insects (Sternorrhyncha: Coccoidea): 20 million years of intimate symbiosis. American Museum Novitates 3335: 1-18.
 * Pfeiffer M.; Mezger, D.; Hosoishi, S.; Bakhtiar, E. Y.; Kohout, R. J. 2011. The Formicidae of Borneo (Insecta: Hymenoptera): a preliminary species list. Asian Myrmecology 4:9-58
 * Shattuck S. O. 1994. Taxonomic catalog of the ant subfamilies Aneuretinae and Dolichoderinae (Hymenoptera: Formicidae). University of California Publications in Entomology 112: i-xix, 1-241.
 * Sukimin S., M. Mohamed, and H. Aris. 2010. Ant diversity of Maliau Basin Conservation Area, Sabah, Malaysia. Journal of Tropical Biology and Conservation 6:89-101.
 * Yamane S.; Nona, A. R. 1994. Ants from Lambir Hills National Park, Sarawak. Pp. 222-226 in: Inoue, T.; Hamid, A. A. (eds.) 1994. Plant reproductive systems and animal seasonal dynamics. Long-term study of dipterocarp forests in Sarawak. Kyoto: Center for Ecological Research, Kyoto University, vii + 255 pp.