Technomyrmex albipes

Bolton (2007) - T. albipes is an extremely successful tramp species that nests and forages both terrestrially and arboreally, and may enter houses. Workers may be found under stones, in and under fallen wood and in tree stumps, on the forest floor and in the leaf litter, on low vegetation and in twigs, on tree trunks and up into the canopy. A single record is known from internodes of the myrmecophyte Humboldtia laurifolia, from Gilimale in Sri Lanka. They also colonise more restricted spaces such as plant spathes and rot holes in wood and they attend a wide range of homopterous insects for honeydew. Although usually regarded as a pest or invasive species, for instance Sulaiman (1997) observes that it tends the mealybug responsible for pineapple wilt disease in Sri Lanka, albipes also has value as an important predator of the eggs of destructive insect species on coconuts in Sri Lanka (Way, Cammell, et al. (1989).

Identification
Bolton (2007) - A member of the T. albipes complex in the Technomyrmex albipes group. Colour of the mandibles and antennae is variable in albipes. The mandible varies from the same dark colour as the head capsule to yellowish, with all intermediate shades present. The scape is usually about the same shade as the head capsule; the funiculus may be the same colour or entirely lighter, or the apical few segments alone may be lighter. These variations are gradient and are not considered taxonomically significant.

In the past many samples of small, darkly coloured Technomyrmex in which the gaster is setose and the tarsi are white or yellow have been misidentified as T. albipes, but in particular albipes has been confused with Technomyrmex vitiensis, Technomyrmex difficilis, Technomyrmex pallipes, Technomyrmex brunneus, Technomyrmex jocosus and Technomyrmex moerens. The first three of these are also common tramp species and vitiensis was for a while considered ajunior synonym of albipes. T. vitiensis, along with its Afrotropical relative moerens, closely resembles albipes, but both have larger eyes, longer scapes and a longer promesonotum than to albipes. Also, the mesonotal profile in albipes workers is evenly curved, whereas in both other species there tends to be an angle or step in the outline, resulting in differently sloped dorsal and declivitous mesonotal faces; see also the notes under vitiensis. As for difficilis, the presence in that species of a pair of setae on the dorsal head behind the level of the posterior margin of the eye easily distinguishes them. However, workers of difficilis in which the head is abraded are difficult to distinguish from albipes; see notes under difficilis. T. pallipes should not be confused with albipes as it always has two pairs of short stubbly setae on the dorsal head behind the level of the posterior margin of the eye. T. brunneus has mandibular grooves not seen in albipes, as well as other different characters, and jocosus has a very different arrangement of setae: neither should be confused with albipes.

Distribution based on Regional Taxon Lists
Afrotropical Region: Cameroun, Ivory Coast, Mozambique, South Africa, Sudan, United Arab Emirates, United Republic of Tanzania, Yemen. Australasian Region: Australia. Indo-Australian Region: Borneo, Cook Islands, Fiji, Guam, Hawaii, Indonesia, Krakatau Islands, Malaysia, Marshall Islands, Micronesia (Federated States of), New Guinea, Niue, Philippines, Pitcairn, Solomon Islands, Sulawesi, Tokelau, Wallis and Futuna Islands. Malagasy Region: Madagascar, Mauritius, Réunion, Seychelles. Neotropical Region: Cayman Islands. Oriental Region: Bangladesh, Cambodia, India, Laos, Sri Lanka, Taiwan, Vietnam. Palaearctic Region: China, Democratic Peoples Republic of Korea, Denmark, Japan, Republic of Korea.

Biology
A member of the T. albipes complex in the Technomyrmex albipes group.

Sharaf et al. (2018): Technomyrmex albipes nests and forages in and beneath fallen wood and rocks, in tree trunks, in leaf litter, in twigs, on the forest floor, on low vegetation, and into the canopy (Bolton 2007). The species is known to feed on honeydew of a broad range of sap sucking attended hemipterans including the mealybug vectors of pineapple wilt disease (Sulaiman 1997).

Yamane et al. (2018) - Although Bolton (2007) resolved most taxonomic confusion in this species group, there still remain some unsolved problems. For example, very restricted information is available about the nesting habits of T. albipes in spite of its common occurrence as a tramp. Bolton enumerated a few instances for the nesting site of this species, namely, internodes of a myrmecophyte, plant spathes and rot holes in wood. However, some carton nests on tree leaves have been found in Borneo and Malay Peninsula for ‘this species’ as well as nests in restricted spaces such as rotting wood, dead twigs etc. (Yamane and Tsuji, personal obs.). This suggests that T. albipes (sensu Bolton) may actually be a complex of sibling species. More information on nesting site and DNA data from various localities are needed to resolve this problem.

Castes
Bolton (2007) - Distinct morphological intercastes between workers and queens, such as are relatively common in Technomyrmex vitiensis, Technomyrmex moerens, Technomyrmex brunneus, Technomyrmex pallipes and other species of the albipes group, where ocelli are present and the mesoscutellum and metanotum are developed as separate or semi-separate sclerites in otherwise worker-like forms, appear absent from material examined of genuine albipes. Only a few basically very worker-like forms with slightly posteriorly expanded mesonota have been seen. This observation may be merely a sampling artifact indicating that most albipes material examined has been of foragers, not from nest samples, as in other species where intercastes have been confirmed they are confined to reproductive behaviour within colonies and do not undertake foraging activities. However, 24 samples provided in alcohol by Martin Pfeiffer (Universitat Ulm), collected at Banting, West Malaysia and Tawau, Sabah, East Malaysia, failed to produce a single obvious intercaste, although many of the samples included brood and fragments of nest material; one had brood and ergatoid males in it and another contained a dealate queen.

Nomenclature

 * detorquens. Formica detorquens Walker, 1859: 372 (q.) SRI LANKA. Combination in Technomyrmex: Donisthorpe, 1932b: 575. Senior synonym of forticulus: Donisthorpe, 1932b: 575. Nomen oblitum, synonym of albipes: Bolton, 2007a: 68. See also: Wilson & Taylor, 1967: 84.
 * forticulus. Crematogaster forticulus Walker, 1859: 372 (q., not w.) SRI LANKA. Junior synonym of detorquens: Donisthorpe, 1932b: 576; nomen oblitum, synonym of albipes: Bolton, 2007a: 68.
 *  albipes. Formica (Tapinoma) albipes Smith, F. 1861b: 38 (w.) INDONESIA (Sulawesi). Forel, 1891b: 98 (q.); Forel, 1908a: 21 (ergatoid m.); Karavaiev, 1926d: 441 (m.); Wheeler, G.C. & Wheeler, J. 1951: 205 (l.); Crozier, 1969: 245 (k.). Combination in Tapinoma: Mayr, 1863: 455; in Technomyrmex: Emery, 1888d: 392. Senior synonym of nigrum: Mayr, 1872: 147; Mayr, 1876: 83; of albitarse: Emery, 1893f: 249; of bruneipes, detorquens, forticulus, wedda: Bolton, 2007a: 68.
 * nigrum. Tapinoma nigrum Mayr, 1862: 703 (w.) SRI LANKA. Junior synonym of albipes: Mayr, 1872: 147; Mayr, 1876: 83; Bolton, 2007a: 68.
 * albitarse. Tapinoma albitarse Motschoulsky, 1863: 14 (w.q.) SRI LANKA. Junior synonym of albipes: Emery, 1893f: 249.
 * bruneipes. Technomyrmex albipes var. bruneipes Forel, 1895e: 466 (w.q.m.) INDIA. Raised to species: Collingwood & Agosti, 1996: 361. Junior synonym of albipes: Bolton, 2007a: 68.
 * wedda. Technomyrmex albipes r. wedda Forel, 1913e: 663 (w.q.) SRI LANKA. Junior synonym of albipes: Bolton, 2007a: 68.

Type Material
Bolton (2007) - Syntype workers, Indonesia: Sulawesi, “Tond” (= Tondano) (A.R. Wallace) [examined].



Worker
Bolton (2007) - TL 2.4 - 2.9, HL 0.56 - 0.63, HW 0.52 - 0.58, SL 0.48 - 0.58, PW 0.35 - 0.42, WL 0.66 - 0.78 (50 measured). Indices: CI 87 - 95, SI 91 - 102, or 24 - 27, EPI 70 - 88, DTI 110 - 124.

Frontal carina with 2 (very rarely 3) setae: in profile the anteriormost seta at the torulus, the posteriormost seta approximately at the level of the anterior margin of the eye. Dorsum of head posterior to this entirely lacks setae. With head in full-face view the anterior clypeal margin with a very weak, shallow median indentation; sides of head shallowly convex and the posterior margin with a small shallow indentation medially. Eyes located in front of midlength, EPI < 90; outer margin of eye usually just fails to break, or sometimes just touches, the outline of the side. With mesosoma in profile the mesonotal outline is evenly curved, without a distinct step or angle in the outline that defines conspicuous dorsal and declivitous faces. Number of setal pairs on mesosoma: pronotum 1 - 3; mesonotum 0 1 (usually 0); propodeal dorsum 0; lateral margins of propodeal declivity 1 - 2 (very rarely 3), usually with one just above the spiracle, another higher up. With the propodeum in profile its dorsum and declivity meet in a short, blunt, but very narrowly rounded curve, not a distinct sharp angle. Straight-line length of propodeal dorsum in profile is less than depth of declivity to spiracle. Gastral tergites 1 - 4 each with numerous setae, distributed everywhere on the sclerites; maximum length of setae on first gastral tergite is usually slightly less than the maximum diameter of the eye but sometimes the two are subequal. Head, mesosoma, petiole and gaster blackish brown to black; in profile the gaster is often slightly lighter than the mesosoma. Coxae, femora and tibiae uniformly blackish brown to black, same colour as the mesosoma or gaster; never with strongly contrasting lighter coxae. Tarsi of middle and hind legs white to dull yellowish, paler than the tibiae.

Determination Clarifications
The correct identities of some species referred to as albipes in relatively recent publications can be ascertained with some degree of certainty, but those of earlier studies (e.g. Starcke, 1940), and even some more recent ones (e.g. Brophy, 1994) in the absence of the relevant specimens, must remain equivocal. Material mentioned as introductions in British hothouses by Donisthorpe (1927) consists of series of albipes, Technomyrmex vitiensis and Technomyrmex pallipes. References to albipes in recent Chinese and Japanese works such as Imai, Hikara, Kondoh, et al. (2003), Zhou (2001), Wu & Wang (1995) and the intensive studies by Tsuji, Furukawa, et al. (1991), Yamauchi, Furukawa, et al. (1991), Tsuji & Yamauchi (1994) and Ogata. Murai, et al. (1996), are all Technomyrmex brunneus. Also referable to brunneus is Radchenko’s (2005) record of “albipes” from North Korea. The discussions of albipes in Bourke & Franks (I 995}, based on these Japanese publications, should also be referred to brunneus. Recent Australian references to albipes in Shattuck (1999), and Andersen's (2000) unnamed fig. 29 are probably all Technomyrmex difficilis and this is also the species which has recently colonised Florida so successfully (Deyrup, 1991; Vail, Davis, et al., 1994; DeyruJl, Davis & Cover, 2000; Warner, 2003). The species referred to as albipes by Brown (l958) in New Zealand is probably Technomyrmex jocosus. The short discussion of albipes by Shattuck (1992b) appears to be a fusion of several species; it certainly includes vitiensis as that is the only species known to occur in conservatories in Golden Gate Park, California. The vast amount of Pacific Islands material listed in Wilson & Taylor (1967) certainly includes both albipes and vitiensis, and probably also difficilis; a critical re-assessment of the entire collection would be needed to resolve the identities. Terron (1972) presented some notes on alate and ergatoid males of a species close to albipes, which may refer to Technomyrmex moerens or perhaps even pallipes.