Tapinoma melanocephalum

The ghost ant, Tapinoma melanocephalum, is an ubiquitous indoor and outdoor pest throughout much of the tropics and subtropics, and an increasingly common indoor pest in temperate regions.

Identification
Distinctively bicoloured, head brown, alitrunk and gaster pale yellowish with variable brown patches; legs and antennae very pale. Prothorax laterally compressed, broadening anteriorly. Length: 1.5-2 mm. (Collingwood 1979)

Distribution
Tapinoma melanocephalum has one of the widest distributions known for any ant species. It has spread across the Old World and New World in both the northern and southern hemispheres. It is tropical and subtropical; at latitudes greater than 30°, it is largely restricted to living inside buildings. The only ants with broader known distributions than T. melanocephalum are the longhorn crazy ant, Paratrechina longicornis, and the pharaoh ant, Monomorium pharaonis. I expect that T. melanocephalum will eventually spread to the disturbed lowlands of virtually every tropical country. This species also appears to be an increasingly common indoor pest in temperate areas, and some-day may be found in every major city of the world. Because T. melanocephalum can live anywhere that humans live, there is no limit to the latitude where indoor populations of this species may be found. (Wetterer 2009)

Distribution based on Regional Taxon Lists
Afrotropical Region: Cape Verde, Comoros, Guinea, Saint Helena, Senegal, Socotra Archipelago, United Arab Emirates, Yemen. Australasian Region: Australia, New Caledonia, Norfolk Island. Indo-Australian Region: Borneo, Cook Islands, Fiji, French Polynesia, Guam, Hawaii, Indonesia, Krakatau Islands, Malaysia, New Guinea, Niue, Philippines, Samoa, Singapore, Solomon Islands, Tokelau, Tonga, Vanuatu, Wallis and Futuna Islands. Malagasy Region: Madagascar, Mauritius, Mayotte, Réunion, Seychelles. Nearctic Region: Canada, United States. Neotropical Region: Anguilla, Bahamas, Barbados, Belize, Brazil, Cayman Islands, Colombia, Costa Rica, Cuba, Dominican Republic, Ecuador, French Guiana, Galapagos Islands, Guadeloupe, Guatemala, Guyana, Haiti, Honduras, Lesser Antilles, Mexico, Paraguay, Puerto Rico, Suriname, Trinidad and Tobago. Oriental Region: Bangladesh, Cambodia, India, Laos, Nicobar Island, Sri Lanka, Thailand. Palaearctic Region: Afghanistan, Belgium, Canary Islands, China, Czech Republic, Finland, Hungary, Iberian Peninsula, Japan, Oman, Republic of Korea, Romania, Russian Federation, Spain, Ukraine, United Kingdom of Great Britain and Northern Ireland.



Biology
Wetterer (2009) - "Tapinoma melanocephalum is a ubiquitous pest through much of the tropics and subtropics. As Longino (2006) aptly wrote: "regardless of whether you are in Guinea, New Guinea, or Guyana, if you are sitting at a table with a sugar dispenser you are likely to see workers of T. melanocephalum running about on the surface." Workers are small (~ 1.5 mm) and their pale legs and abdomens often blend into the background, making them difficult to see. Their dark brown heads and thoraces often look like hovering specks, unrecognizable as ants. The barely visible "ghostly" appearance of T. melanocephalum no doubt explains its common name.

Tapinoma melanocephalum is particularly noted as a pest in homes, restaurants, hospitals, and greenhouses. For example, T. melanocephalum was the most common house ant in Brazil (e.g., Kamura et al. 2007) and on Panang Island, Malaysia (Lee et al. 2002), and it was the most fre-quently reported pest ant in greater Miami (Klotz et al. 1995). Wheeler (1907) noted that T. melanocephalum had been "introduced into well-heated buildings in New York," and observed workers in the winter "visiting the sugar bowls on the tables of the Columbia University commons." Karawajew (1926) reported T. melanocephalum from hotel tables both on Ambon Island, Indonesia and in Vladivostok, Russia. James Trager (pers. comm.) observed T. melanocephalum inside the Sachs Butterfly House in Chesterfield, Missouri, beginning shortly after it opened in 1995. Tapinoma melanocephalum also has been a long term problem in the greenhouses of the Dow Estate in Midland, Michigan, where fumigation is incompatible with a butterfly exhibit (J. LaForest, pers. comm.).

Although T. melanocephalum does not sting and its bite is not very painful (pers. obs.), it can be a serious pest. For example, Fowler et al. (1993) and Moreira et al. (2005) found that T. melanocephalum was the most prevalent ant in hospitals in Brazil, and had the highest potential as a vector for pathogens. In fact, Moreira et al. (2005) found at least 14 different types of bacteria on T. melanocephalum workers collected in the hospitals, including antibiotic resistant strains. Tapinoma melanocephalum also can be an agricultural pest because it tends populations of phloem feeding Hemiptera, such as mealybugs, scale insects, and aphids, for their honeydew (Venkataramaiah and Rehman 1989). Hemiptera cause damage by sapping plants of nutrients and increasing the occurrence of diseases, including viral and fungal infections. Fowler et al. (1994) concluded that T. melanocephalum had a great impact on other ant species on banana plantations in Brazil. Under some conditions, T. melanocephalum may be beneficial as a biocontrol agent. For example, Osborne et al. (1995) found that in greenhouses of central Florida, naturally occurring populations of T. melanocephalum were important in controlling a serious plant pest, the two-spotted spider mite, Tetranychus urticae Koch, 1836.

Whereas T. melanocephalum is most prevalent in disturbed habitats, it has also been reported from natural reserves around the world, including the Baiyer River Wildlife Sanctuary in Papua-New Guinea (Whalen and Mackay 1988), Reserva Biológica de Una in Brazil (Delabie et al. 1997), primary rainforest in Chocó, Colombia (Armbrecht et al. 2001), and on many Galapagos islands (Causten et al. 2006). In the Wapoga River Area of Irian Jaya, Indonesia, Snelling (2000) found that T. melanocephalum "had successfully invaded forest areas where they apparently became quickly assimilated into the native mix; their presence did not seem to adversely affect other ant species there. This apparently benign situation probably would be reversed in the presence of continued disturbance of the habitat."

Tapinoma melanocephalum colonies are polygynous and frequently relocate their nests. In a matter of hours, colonies can move into cargo, which is then shipped worldwide. In fact, Lester (2005) reported that T. melanocephalum was the second most common ant species (after Pheidole megacephala) intercepted in freight entering New Zealand between 1997 and 2002. Weber (1939) reported collecting T. melanocephalum from riverboats in Venezuela and Guyana and on a ship between Haiti and New York. Tapinoma melanocephalum was found on a train in France, traveling from Paris to Rennes (X. Espadaler, pers. comm.). In Le Carbet, Martinique, a T. melanocephalum colony moved overnight into luggage packed for departure, requiring me to shake out everything before repacking."

Klimes and Okrouhlik (2015) - One of the most frequently recorded pests in hospitals in the tropics. . . In buildings, it is usually seen in kitchen corridors and bathrooms. . . Despite their diminutive size, workers are able to use their mandibles to penetrate even the thick plastic of sugar packages.

Regional Notes
Espadaler (2007) - Canary Islands: Running workers were detected in irrigated gardens next to recently built bungalows. This is the first record for El Hierro of this well known tramp species.

Klimes and Okrouhlik (2015) report on a indoor infestation in an apartment complex in South Bohemia, Czech Republic. This is the first time Tapinoma melanocephalum has been recorded from the country.

This species is common in south Florida, to Volusia county. Almost always in disturbed areas, in many sites seems confined to areas around buildings. Nests are in bark mulch, under objects on the ground, and under loose bark and the bases of palm fronds. Pest status: can enter buildings through screens and small cracks, becoming a general annoyance. First published Florida record: Smith 1930. (Deyrup, Davis & Cover, 2000.)

Sharaf et al. (2017) - Yemen: The nesting and foraging habitats of this species are diverse. Several specimens were found foraging on a tree located on a mountainside with nearby stream drainage. The area had moist soils with high plant diversity, especially Adiantum capillus-veneris L. (Pteridaceae), which was abundant. The area was dominated by the ponerine ant, Brachyponera sennaarensis (Mayr, 1862). A nest series was collected from an area with moist soil and dense grasses. The area was rich in decayed animal faeces. Another nest was collected by sifting the leaf litter next to a stream and small pool with many scattered date palm (Phoenix dactylifera L.) trees. Another nest series was found under the bark of a recently cut dragon blood tree, Dracaena cinnabari Balf.f. (Asparagaceae) and associated with curculionid beetles. This invasive species has a broad range of habitat preference worldwide (Wetterer 2009a), including pre-existing cavities made of plant materials, and in larders and pantries, and nesting in walls and potted plants indoors (Ellison et al. 2012).

Foraging/Diet
An experimental study by Zhou et al. (2015) tested effects of ant tending, host plants, parasitism and their interactions on mealybugs on two host plant species. The plants, tomato (Solanum lycopersicun) and cotton (Gossypium hirsutum), were grown in a greenhouse at an agricultural field station near Guangzhou, China. The ants (Tapinoma melanocephalum), hemipterans (Phenacoccus solenopsis Tinsley) and parasitoid (Aenasius bambawalei Hayat) were collected from local habitats, i.e., are naturally sourced and locally occurring species that are known to interact with one another. They found that mealybug benefits from ant attendance by T. melanocephalum did differ by host plant. The ant tending was more intense on tomato versus cotton plants. The mealybugs showed both a higher growth rate with higher ant attendance and a decrease in parasitism rate. In sum, they found the tomato plants likely produced higher quality honeydew, stimulating ant attendance, and this in turn provided positive benefits to the hemiptera.

Other Insects
This ant has been observed tending larvae of Lampides boeticus (Obregon et al. 2015).

Chemistry
Shi et al. (2017) - Abstract Volatile compounds in Tapinoma melanocephalum (Fabricius) (Hymenoptera: Formicidae, Dolichoderinae) workers were analyzed using gas chromatography–mass spectrometry and electroantennogram responses of workers to these compounds were investigated using coupled gas chromatography–electroantennographic detection. Among 18 detected compounds, six elicited electroantennogram response, including 6-methyl-5-hepten-2-one, 4 iridodials, and (Z)-9-nonadecene. (Z)-9-Nonadecene and iridodials were identified the first time in T. melanocephalum. (Z)-9-Nonadecene is a major component in mandibular glands and iridodials are produced in pygidial glands. In contrast to previous report, actinidine was not found in pygidial glands. Behavioral response of workers to the synthetic (Z)-9-nonadecene was investigated. (Z)-9-nonadecene is an attractant to T. melanocephalum. It also affected their locomotion patterns.

Worker
Additional worker images can be found here

Nomenclature

 *  melanocephalum. Formica melanocephala Fabricius, 1793: 353 (w.) FRENCH GUIANA. Emery, 1887a: 249 (m.); Forel, 1891b: 102 (q.); Wheeler, G.C. & Wheeler, J. 1951: 197 (l.); Crozier, 1970: 119 (k.). Combination in Micromyrma: Roger, 1862b: 258; in Tapinoma: Mayr, 1862: 651; in Tapinoma (Micromyrma): Santschi, 1928e: 475. Senior synonym of pellucida: Mayr, 1886c: 359; of nana: Emery, 1892b: 166; of familiaris: Forel, 1899c: 101; of australis: Wilson & Taylor, 1967: 80; of australe: Bolton, 1995b: 401. Current subspecies: nominal plus coronatum, malesianum. See also: Smith, D.R. 1979: 1421; Shattuck, 1994: 148.
 * nana. Formica nana Jerdon, 1851: 125 (w.) INDIA. [Unresolved junior primary homonym of Formica nana Latreille, 1802c: 263.] Junior synonym of melanocephalum: Emery, 1892b: 166.
 * pellucida. Myrmica pellucida Smith, F. 1857a: 71 (w.) SINGAPORE. Junior synonym of melanocephalum: Mayr, 1886c: 359.
 * familiaris. Formica familiaris Smith, F. 1860b: 96 (w.) INDONESIA (Batjan I.). [Unresolved junior primary homonym of Formica familiaris Smith, F. 1860a: 68 (now in Pseudolasius).] Junior synonym of melanocephalum: Forel, 1899c: 101.
 * australe. Tapinoma (Micromyrma) melanocephalum var. australe Santschi, 1928e: 475 (w.) VANUATU. Junior synonym of melanocephalum: Bolton, 1995b: 399. [Note. Shattuck, 1994: 148 treats australis and australe as variant spellings, but the type-localities of the two are different and the names must be treated as separate.]
 * australis. Tapinoma (Micromyrma) melanocephalum var. australis Santschi, 1928a: 53 (w.) SAMOA. Junior synonym of melanocephalum: Wilson & Taylor, 1967: 80.

Type Material


Formica familiaris

Holotype queen in. Labelled “Mak.” (= Makassar, Sulawesi).

Myrmica pellucida

Four worker syntypes in. Without a locality label on the specimens, but with a Smith det. label. Locality given in original description is Singapore.