Monomorium pharaonis

Arguable the most ubiquitous house ant in the world.

Identification
Wetterer (2010) - Monomorium pharaonis workers vary in color, even within a colony, from uniform yellow to yellow with a dark brown rear of the gaster. Several other Monomorium species are also known as tramp ants, transported worldwide through human commerce, including Trichomyrmex destructor (JERDON, 1851), Monomorium floricola (JERDON, 1851), Monomorium monomorium BOLTON, 1987, Syllophopsis sechellensis (Emery, 1894), and Monomorium subopacum (SMITH, 1858). Of these tramp species, M. pharaonis resembles only M. destructor in color, but has a much narrower range of worker size (M. pharaonis: 2.2 - 2.4 mm length; M. destructor: 1.8 - 3.5 mm length; BOLTON 1987). Monomorium pharaonis also can be easily distinguished from M. destructor because the head, mesosoma, petiole, and postpetiole of the workers are matte (not shiny) in M. pharaonis, but are almost entirely smooth and shiny in M. destructor.

Distribution
Found throughout the world. Wetterer, 2010 is the most recent distribution study of this species.

Distribution based on Regional Taxon Lists
Afrotropical Region: Angola, Cameroun, Central African Republic, Eritrea, Ghana, Guinea, Ivory Coast, Kenya, Liberia, Mali, Mozambique, Nigeria, Senegal, Sudan, United Republic of Tanzania, Zimbabwe. Australasian Region: Australia, New Zealand. Indo-Australian Region: Borneo, Fiji, Guam, Hawaii, Indonesia, Kiribati, Malaysia, Marshall Islands, Micronesia (Federated States of), New Guinea, Northern Mariana Islands, Philippines, Samoa, Singapore, Solomon Islands, Vanuatu. Malagasy Region: Réunion, Seychelles. Nearctic Region: Canada, United States. Neotropical Region: Argentina, Bahamas, Bolivia, Brazil, Chile, Colombia, Costa Rica, Cuba, Dominican Republic, Ecuador, French Guiana, Greater Antilles, Guyana, Mexico, Panama, Paraguay, Peru, Puerto Rico, Suriname, Trinidad and Tobago, Uruguay. Oriental Region: Bangladesh, Cambodia, India, Laos, Sri Lanka, Thailand, Vietnam. Palaearctic Region: Albania, Armenia, Austria, Balearic Islands, Belarus, Belgium, Bulgaria, Canary Islands, China, Croatia, Czech Republic, Democratic Peoples Republic of Korea, Denmark, Egypt, Estonia, Faeroe Islands, Finland, Georgia, Germany, Greece, Hungary, Iberian Peninsula, Iran, Iraq, Israel, Japan, Jersey, Kyrgyzstan, Latvia, Lithuania, Luxembourg, Montenegro, Netherlands, Norway, Poland, Portugal, Republic of Korea, Republic of Moldova, Romania, Russian Federation, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey, Turkmenistan, Ukraine, United Kingdom of Great Britain and Northern Ireland.

Biology
Bolton (1987) - One of the world's best known, most widely distributed and most successful tramp-species, not only in the genus Monomorium but in the family Formicidae as a whole, pharaonis has been recorded as a major domestic pest for well over a century. Records as early as Bostock (1838) and Jerdon (1851) indicate its remarkable house-infesting propensities and its peculiar ability to nest in any available small cavity once inside a dwelling.

The past few decades have seen an incredible increase in the range and population density of this species in the temperate zones of the world, corresponding to a large extent with the spread of high-density apartment blocks and central heating systems; the species can persist outdoors only under exceptional circumstances outside the tropics (Kohn & Vicek, 1986). A direct result of the ant so thrusting itself into the public notice has been a welter of papers investigating all aspects of its life-history, behavior and control. It is impractical to present a full bibliography here, but all salient features of studies on pharaonis can be obtained from the following short bibliography, and the further references included in the publications cited.

Earlier literature is summarized in Wheeler (1922), Smith (1934), and Peacock et al. (1950); the exhaustive list given in Krombein et al. (1979) should also be consulted. Introductory and general information is given in Sudd (1967), Wilson (1971) and Dumpert (1978). More specialized aspects of studies on pharaonis can be obtained from the following.

Mass rearing and laboratory culture of colonies: Kretzschmar (1971); Buschinger & Petersen (1971); Berndt & Kremer (1980) ; Samsinak et al. ( 1984).

Control techniques: Eichler & Kleinsorge (1973); Berndt & Nitschmann (1977); Rupes et al. (1983). Summary of pheromone studies: Czechowski (1979).

Aspects of biology and ethology: Lauterer (1971) ; Petersen & Buschinger (1971a, 1971b); Beatson (1972); Eichler & Kleinsorge (1972); Holldobler (1973); Petersen-Braun (1977, 1982); Berndt & Nitschmann (1979).

An interesting series of papers describing the establishment, distribution, biology and attempted eradication of pharaonis in Poland is given in Wisniewski et al. (1971); Czajkowska (1979); Krzeminska et al. (1979).

Collingwood (1979) Colonies are very large, polygynous and polycalic often with several millions of individuals. Workers and queens forage in long trails and live by scavenging on food materials, dead animals and insects. Nests are often sited deep in foundations and are very difficult to eradicate by fumigation or insecticides.

Florida
A common species in Florida, occurring throughout the state. Nests are in and around buildings; it is an aggressive scavenger that makes conspicuous foraging trails. It is highly polydomous, and correspondingly difficult to eradicate. Pest status: this is the most persistent of Florida ant pests that breed indoors. In recent years baits have been developed that effectively control this ant. Although it rarely stings, it is very annoying in other ways, appearing in huge numbers in kitchens in homes and institutions, and frequently infesting rooms in hospitals and nursing homes. It often gnaws through the packaging of candy bars or breakfast cereal to infest the contents. First published Florida record: Smith 1930; earlier specimens: 1908. (Deyrup, Davis & Cover, 2000.)

Associations with Humans
Wetterer (2010) Monomorium pharaonis is particularly notorious as a pest in hospitals, where it is known as a vector for disease. In tropical areas, M. pharaonis occurs both indoors and out, but in temperate areas, it is found almost exclusively indoors. It is by far the most common tropical ant found in heated buildings of Europe and North America.

Nomenclature

 *  pharaonis. Formica pharaonis Linnaeus, 1758: 580 (w.) EGYPT. Mayr, 1865: 90 (m.); André, 1883a: 338 (q.); Forel, 1891b: 164 (w.q.m.); Wheeler, G.C. & Wheeler, J. 1955c: 121 (l.); Petralia & Vinson, 1980: 383 (l.); Imai, 1966: 119 (k.). Combination in Monomorium: Mayr, 1862: 752. Senior synonym of antiguensis, domestica: Roger, 1862c: 294; of contigua, fragilis: Mayr, 1886c: 359; of minuta: Emery, 1892b: 165; Bolton, 1987: 288; of vastator: Donisthorpe, 1932c: 449. See also: Smith, D.R. 1979: 1383; Bolton, 1987: 356; Atanassov & Dlussky, 1992: 164; Heterick, 2006: 100.
 * antiguensis. Formica antiguensis Fabricius, 1793: 357 (w.) WEST INDIES. Junior synonym of pharaonis: Roger, 1862c: 294.
 * domestica. Myrmica domestica Shuckard, 1838: 627 (w.q.) GREAT BRITAIN. Smith, F. 1851: 119 (m.). Junior synonym of pharaonis: Roger, 1862c: 294. See also: Curtis, 1854: 217; Bolton, 1987: 356.
 * minuta. Atta minuta Jerdon, 1851: 105 (w.q.) INDIA. Junior synonym of pharaonis: Emery, 1892b: 165; Bolton, 1987: 288, 356.
 * vastator. Myrmica vastator Smith, F. 1857a: 71 (w.) SINGAPORE. Combination in Monomorium: Mayr, 1886c: 359. Junior synonym of destructor: Dalla Torre, 1893: 66; of pharaonis: Donisthorpe, 1932c: 449.
 * contigua. Myrmica contigua Smith, F. 1858b: 125 (q.) SRI LANKA. Junior synonym of pharaonis: Mayr, 1886c: 359.
 * fragilis. Myrmica fragilis Smith, F. 1858b: 124 (w.) SINGAPORE. Junior synonym of pharaonis: Mayr, 1886c: 359.

Type Material


Heterick 2006:

Syntype workers, EGYPT [whereabouts of type material unknown]

M. vastator: LECTOTYPE: worker, Singapore, J. Smith. Four syntype workers are carded, two above and two below, on the one pin. The worker on the lower left-hand side (viewed from the rear of the pin) is here designated a lectotype to fix the name ‘vastator’ in the interests of stability. Monomorium pharaonis belongs to a small complex of closely related ants, and was also confused with Monomorium destructor by early researchers (Bolton 1987). PARALECTOTYPES: Three workers, same data as the lectotype (OXUM). (The lectotype and three paralectotypes are covered with a uniform, thin layer of glue and cannot be separated.).

Formica pharaonis L. 1758:580. Syntype ☿'s, EGYPT [whereabouts of type material unknown]

Formica antiguensis Fabricius 1793:357. Syntype ☿, WEST INDIES: Antigua [whereabouts of type material unknown]. Syn. under M. pharaonis (L.): Roger 1862b: 294.

Myrmica domestica Shuckard 1838:627. Syntype ☿'s, GREAT BRITAIN: London [no types known to exist]. Syn. under M. pharaonis (L.): Roger 1862b:294.

Atta minuta Jerdon 1851:105. Syntype ☿'s, INDIA [no types known to exist]. Syn. under M. pharaonis (L.): Emery1892:165.

Myrmica vastator Smith 1857:71. Syntype ☿'s (lectotype here designated), SINGAPORE [examined].

Myrmica fragilis Smith 1858:124. Syntype ☿'s (lectotype here designated), SINGAPORE [examined]. Syn. under M. pharaonis (L.): Mayr 1886:359.

Myrmica contigua Smith 1858:125. Holotype, SRI LANKA [examined]. Syn. under M. pharaonis (L.): Mayr 1886:359.

Bolton Smith Types

Myrmica vastator

Four worker syntypes in. Locality label is missing (should be “SING.”), but Wallace’s original note, “House ants Singapore, very destructive,” is still attached.

Worker
Heterick 2006 - LECTOTYPE (M. vastator): The physical condition and alignment of the worker does not permit ready measurements. LECTOTYPE (M. fragile): HML 1.52 HL 0.56 HW 0.42 CeI 75 SL 0.48 SI 114 PW 0.23. OTHER WORKERS: HML 1.39–1.48 HL 0.53–0.56 HW 0.42–0.45 CeI 78–81 SL 0.45–0.49 SI 105–111 PW 0.22–0.28 (n=8).

HEAD: Head oval; vertex weakly convex; frons shining and finely striolate and microreticulate; pilosity of frons consisting of a few short, thick, erect setae interspersed with short, appressed setulae. Eye moderate, eye width 1–1.5× greatest width of antennal scape; (in full-face view) eyes set above midpoint of head capsule; (viewed in profile) eyes set posteriad of midline of head capsule; eye elliptical, curvature of inner eye margin may be more pronounced than that of its outer margin. Antennal segments 12; antennal club three-segmented. Clypeal carinae indicated by multiple weak ridges; anteromedian clypeal margin broadly convex; paraclypeal setae moderately long and fine, curved; posteromedian clypeal margin approximately level with antennal fossae. Anterior tentorial pits situated nearer antennal fossae than mandibular insertions. Frontal lobes straight, parallel. Psammophore absent. Palp formula 2,2. Mandibular teeth four; mandibles with sub-parallel inner and outer margins, striate; masticatory margin of mandibles approximately vertical or weakly oblique; basal tooth approximately same size as t3 (four teeth present).

MESOSOMA: Promesonotum shining and microreticulate throughout; (viewed in profile) promesonotum broadly convex; promesonotal setae two to six; standing promesonotal setae consisting of very short, incurved decumbent setae only; appressed promesonotal setulae well-spaced over entire promesonotum. Metanotal groove strongly impressed, with distinct transverse costulae. Propodeum shining and microreticulate; propodeal dorsum flat throughout most of its length; propodeum smoothly rounded or with indistinct angle; standing propodeal setae consisting of one prominent pair anteriad, with other shorter setae very sparse or absent; appressed propodeal setulae well-spaced and sparse; propodeal spiracle equidistant from metanotal groove and declivitous face of propodeum. Vestibule of propodeal spiracle absent or not visible. Propodeal lobes present as blunt-angled flanges.

PETIOLE AND POSTPETIOLE: Petiolar spiracle lateral and situated within anterior sector of petiolar node; node (viewed in profile) conical, vertex tapered; appearance of node shining and distinctly microreticulate; ratio of greatest node breadth (viewed from front) to greatest node width (viewed in profile) about 1:1; anteroventral petiolar process present as a thin flange tapering posteriad; ventral petiolar lobe present; height ratio of petiole to postpetiole between 4:3 and 1:1; height–length ratio of postpetiole about 1:1; postpetiole shining and microreticulate; postpetiolar sternite not depressed at midpoint, its anterior end an inconspicuous lip or small carina.

GASTER: Pilosity of first gastral tergite consisting of well-spaced, erect and semi-erect setae interspersed with a few appressed setulae.

GENERAL CHARACTERS: Color yellowish, gastral tergites with brown infuscation in basal sector. Worker caste monomorphic.

Queen
Heterick 2006 - HOLOTYPE (M. contiguum): HML 2.43 HL 0.68 HW 0.63 CeI 93 SL 0.62 SI 98 PW 0.73. OTHER QUEENS: HML 2.37 HL 0.66 HW 0.62 CeI 94 SL 0.58 SI 94 PW 0.52 (n=1).

HEAD: Head square; vertex always planar; frons matt and uniformly reticulate-punctate; frons a mixture of well-spaced, distinctly longer erect and semi-erect setae interspersed with shorter setae or setulae, which are decumbent or appressed, longer setae thickest on vertex. Eye elliptical, curvature of inner eye margin may be more pronounced than that of its outer margin; eyes (in full-face view) set at about midpoint of head capsule; eyes (viewed in profile) set around midline of head capsule.

MESOSOMA: Anterior mesoscutum smoothly rounded, thereafter more-or-less flattened; pronotum, mesoscutum and mesopleuron uniformly reticulate-punctate, punctations tending to form fine striolae on dorsum of mesoscutum; length-width ratio of mesoscutum and scutellum combined between 7:3 and 2:1. Axillae narrowly separated (i.e., less than width of one axilla). Standing pronotal/mesoscutal setae consisting of well-spaced, incurved, erect and semi-erect setae only; appressed pronotal, mescoscutal and mesopleural setulae well-spaced over entire surface. Propodeum uniformly reticulate-punctate; always smoothly rounded; propodeal dorsum convex; standing propodeal setae consisting of two or more pairs of prominent setae anteriad, with a few decumbent setae around declivitous face; appressed propodeal setulae well-spaced and sparse; propodeal spiracle equidistant from metanotal groove and declivitous face of propodeum; propodeal lobes present as bluntly angled flanges.

WING: Wing not seen (queen dealated).

PETIOLE AND POSTPETIOLE: Petiolar spiracle lateral and situated within anterior sector of petiolar node; node (viewed in profile) conical, vertex tapered; appearance of node matt and reticulate-punctate; ratio of greatest node breadth (viewed from front) to greatest node width (viewed in profile) about 1:1. Anteroventral petiolar process absent or vestigial; height ratio of petiole to postpetiole about 1:1; height–length ratio of postpetiole about 4:3; postpetiole matt and reticulate-punctate; postpetiolar sternite forming a narrow wedge-shaped projection through strong convergence of its anterior and posterior ends.

GASTER: Pilosity of first gastral tergite consisting of well-spaced, erect and semi-erect setae interspersed with a few appressed setulae.

GENERAL CHARACTERS: Color orange-yellow, gaster brown, with large, yellow sector at apex of first tergite. Brachypterous alates not seen. Ergatoid or worker-female intercastes not seen.