Tetramorium insolens

Tetramorium insolens is a pan-global tramp species with a relatively wide distribution range and is now considered invasive (Roberts & McGlynn, 2004). It was originally described from Sulawesi, Indonesia, and has since been recorded from other Indonesian islands, Sri Lanka, Philippines, New Guinea, the Solomon Islands, the Hawaiian Islands, and several more Pacific islands, but also from Los Angeles, California, England, and Germany (Bolton, 1977, 1979). Its distribution might be even larger than as described above since T. insolens often has been misidentified as Tetramorium bicarinatum in the past (Bolton, 1977); thus, many other introductions might have occurred without being noticed. (Hita Garcia and Fisher 2011)

Identification
The following character combination isolates T. insolens from the other members of the T. bicarinatum group in the Malagasy region: unsculptured mandibles, rectangular petiolar node with posterodorsal angle sharper and higher situated than the more rounded anterodorsal angle, and uniform pale yellow to orange-brown colouration with gaster always of same colour or lighter than the remainder of the body. (Hita Garcia and Fisher 2011)

Identification Keys including this Taxon
Key to US Tetramorium species

Distribution based on Regional Taxon Lists
Australasian Region: New Caledonia. Indo-Australian Region: American Samoa, Borneo, Fiji, Indonesia, New Guinea, Niue, Philippines, Samoa, Solomon Islands, Sulawesi, Tonga, Vanuatu. Malagasy Region: Réunion. Nearctic Region: United States. Neotropical Region: Mexico. Oriental Region: Thailand. Palaearctic Region: China, Hungary, Poland.



Nomenclature

 *  insolens. Myrmica insolens Smith, F. 1861b: 47 (q., not w.) INDONESIA (Sulawesi). Bolton, 1977: 99 (w.); Imai, Kubota, et al. 1985: 47 (k.). Combination in Tetramorium: Emery, 1901g: 567; Donisthorpe, 1932c: 468. Senior synonym of macra, pallidiventre, wilsoni: Bolton, 1977: 99. See also: Hita Garcia & Fisher, 2011: 22.
 * macra. Tetramorium guineense var. macra Emery, 1914f: 415 (w.) NEW CALEDONIA. Junior synonym of insolens: Bolton, 1977: 99.
 * wilsoni. Tetramorium pacificum var. wilsoni Mann, 1921: 460 (w.) FIJI IS. Raised to species: Taylor, 1967b: 1093. Junior synonym of insolens: Bolton, 1977: 99.
 * pallidiventre. Tetramorium melanogyna var. pallidiventre Wheeler, W.M. 1934a: 177 (w.) SOLOMON IS. Junior synonym of insolens: Bolton, 1977: 99.

Worker
Hita Garcia and Fisher (2011) - HL 0.725 - 0.825 (0.775); HW 0.655 - 0.750 (0.698); SL 0.540 - 0.605 (0.576); EL 0.155 - 0.185 (0.170); PW 0.485 - 0.520 (0.503); WL 0.890 - 1.015 (0.953); PSL 0.210 - 0.250 (0.235); PTL 0.245 - 0.300 (0.267); PTH 0.248 - 0.305 (0.276); PTW 0.225 - 0.270 (0.246); PPL 0.225 - 0.270 (0.248); PPH 0.250 - 0.305 (0.274); PPW 0.280 - 0.340 (0.305); CI 89 - 91 (90); SI 81 - 85 (83); OI 24 - 26 (24); PSLI 29 - 32 (30); PeNI 46 - 52 (49); LPeI 91 - 100 (97); DPeI 89 - 96 (92); PpNI 58 - 65 (60); LPpI 87 - 94 (91); DPpI 120 - 127 (123); PPI 119 - 128 (124) (12 measured).

Head distinctly longer than wide (CI 89 - 91). Anterior clypeal margin with median impression. Frontal carinae strongly developed, ending shortly before posterior head margin. Antennal scrobes weakly developed, narrow, shallow, and posterior and ventral margins never differentiated, as long as frontal carinae. Antennal scapes of moderate length, not reaching posterior margin of head (SI 81 - 85). Eyes moderate to relatively large (OI 24 - 26), with 10 to 12 ommatidia in longest row. Metanotal groove absent. Propodeal spines long, spinose, and acute (PSLI 29 - 32). Propodeal lobes short to medium-sized, triangular to elongate triangular, and acute. Node of petiole rectangular nodiform, anterodorsal angle more rounded than sharper posterodorsal angle, anterodorsal angle situated lower than posterodorsal, in profile dorsum weakly rising posteriorly, in dorsal view weakly longer than wide (DPeI 89 - 96), in lateral view slightly longer than high to as long as high (LPeI 91 - 100). Postpetiole roughly rounded, in dorsal view distinctly wider than long (DPpI 120 - 127), and in lateral view weakly higher than long (LPpI 87 - 94). Postpetiole in profile less voluminous than petiolar node, in dorsal view always distinctly wider than petiole (PPI 119 - 128). Mandibles unsculptured, smooth, and shiny. Clypeus longitudinally rugose, usually with three strong rugae. Most of head with reticulate-rugose sculpturation, more rugose between frontal carinae anteriorly close to posterior clypeal margin; ground sculpturation on head weak and faint. Mesosoma and waist segments reticulate-rugose. Gaster completely unsculptured, smooth, and shiny. All dorsal surfaces of head, mesosoma, waist segments and gaster with numerous fine, long, standing hairs; hairs on antennal scapes and tibiae appressed to suberect. Colouration uniformly pale yellow to orange-brown, gaster often lighter than rest of body.

Type Material
Hita Garcia and Fisher 2011:

Holotype queen, INDONESIA, Sulawesi, Menado (A.R. Wallace) [examined].

Tetramorium guineense var. macra Emery, 1914:415. Syntype workers, NEW CALEDONIA, Konè, 8.VIII.1911, (Sarasin & Roux) [examined].

Tetramorium pacificum var. wilsoni Mann, 1921:460. Syntype workers, FIJI ISLAND, Viti Levu, Nausori, Waiyanitu, 1915-1916 (W.M. Mann) [not examined].  Tetramorium melanogyna var. pallidiventre Wheeler, W.M., 1934:177. Holotype worker, SOLOMON ISLANDS, NW end of Bellona Island, 19.VI.1933 (M. Willows) (CASC: CASTYPE05027) [examined].

Myrmica insolens

Holotype queen (not worker) in. Labelled “Men.” (= Menado, Sulawesi). The original description begins “Worker,” but this is a misprint as Smith mentions the presence of black ocelli.