Monomorium pharaonis (Linnaeus, 1758)

Ivanov, Kaloyan, 2016, Exotic ants (Hymenoptera, Formicidae) of Ohio, Journal of Hymenoptera Research 51, pp. 203-226 : 212-213

Monomorium pharaonis (Linnaeus, 1758)

Distribution in Ohio.

Widespread in Ohio. Counties: Cuyahoga (material examined: Cleveland, iii.2007, leg. J.B. Keiper, inside a building, CMNH; also in Headley 1943), Delaware, Franklin (M.R. Smith material in the Ohio State University collection; in Wetterer 2010), Greene and Wayne (see Coovert 2005 and references therein for all listed counties), (Fig. 3 ).

Where found/Habitat.

Indoors, in heated buildings.

Origin.

Asia.

Natural history.

The pharaoh ant is arguably one of the world’s most widespread house-infesting ants and there is a large body of literature on the pest status of this species. According to Wetterer (2010) this ant is by far the most common species encountered indoors in both North America and in Europe. In tropical and subtropical regions it occurs both indoors and in natural settings, although it is rarely collected outdoors in most parts of the world ( Wetterer 2010). Members of the genus Monomorium can be identified by their minute size, 12 segmented antennae with a three segmented club, and the dorsally smooth unarmed propodeum. Workers of Monomorium pharaonis can be separated from other Monomorium species by the densely punctate head and thorax, the yellowish body color, and the often infuscated posterior portion of the gaster.

Like other tramp species Monomorium pharaonis possesses features that facilitate its transport and establishment including highly polygynous and extensively polydomous colonies with little intercolony aggression ( Passera 1994). A major contributing factor to the invasiveness of this ant is the formation of daughter colonies via fragmentation of the main nest. Newly formed nests remain in contact with the natal nest and may continue to exchange individuals after budding ( Buczkowski and Bennett 2009). This results in large polydomous colonies that can quickly monopolize available resources. Inside buildings pharaoh ants breed continuously throughout the year. Mating occurs in the nest and no mating flights have been observed in this species ( Passera 1994). In temperate areas nests are located exclusively inside buildings including wall spaces and foundations, under floors, in potted plants, around household items and in furniture. Workers are omnivorous and form pronounced foraging trails. They scavenge for both dead and live insects, as well as household food items, often exhibiting marked fondness for fats and meats ( Smith 1965, Collingwood 1979).

In northern temperate regions, this small ant is highly synanthropic and depends on humans for food and shelter ( Buczkowski and Bennett 2009). In Ohio, it is known only from people’s homes and other heated buildings. In hospitals, this species can be a major nuisance and a serious health threat due to its ability to spread pathogenic bacteria onto sterile equipment and supplies ( Beatson 1972).

Figures

Figure 3. Distribution of Cardiocondyla obscurior (5), Monomorium pharaonis (6), Pheidole bilimeki (7), Tetramorium atratulum (8), and Hypoponera ragusai (9) in Ohio.