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Monomorium pharaonispharaoh ant

By Daniel Morris

Ge­o­graphic Range

The Pharaoh ant is lim­ited by cool cli­mates, and re­lies upon hu­mans for a suit­able home in north­ern re­gions. This ant orig­i­nates in the Old World trop­ics of Africa and has mi­grated to areas acrss the globe. (Klots and Klots, 1959)

Habi­tat

The di­ver­sity of habi­tats the Pharaoh ant can live in is amaz­ing! In North­ern cli­mates how­ever, their nests often occur within house­holds--the spaces in walls be­tween the studs and in­su­la­tion offer warm breed­ing grounds rel­a­tively hid­den from our [human] eye (Howard, 1908). A major nui­sance in the United States, the Pharoah ant is small, and dif­fi­cult to gauge in pop­u­la­tion size. Their colonies are ru­ined by seal­ing cracks, and cut­ting off ex­po­sure to food. Kerosene has his­tor­i­cally been used for this pur­pose (Klots and Klots 1959). (Howard, 1908; Klots and Klots, 1959; Howard, 1908; Klots and Klots, 1959)

Phys­i­cal De­scrip­tion

Def­i­nitely one of the small­est ants at a mere 1/12 or 1/16 of an inch, their bod­ies are red­dish brown to slightly tan in na­ture (Drees and Jack­man 1998). Each com­pound eye has 20 facets, and each mandible has four teeth. Paired lon­gi­tu­di­nal and metan­o­tal grooves are def­i­nitely dis­tinct. The prod­podeal dor­sum has no "stand­ing hairs" (Ogata, et al 1998).

Pharoah ants (like all in­sects) have three main body sec­tions: tho­rax, head, and ab­domen, and three pairs of jointed legs that are at­tached to the tho­rax. Pharaoh ants use their an­ten­nae to sense vi­bra­tions, and for aid­ing vi­sion in non-lighted areas. Small hairs that may be pre­sent on the ab­domen can aid in sens­ing the weather, or by pro­cess­ing touch. Fi­nally, like all arthro­pods, they con­tain a hard ex­oskele­ton and ad­di­tion­ally have a waxy cu­ti­cle to pre­vent dry­ing out. Arthor­pod skele­tons are made of chitin, a poly­mer de­riv­a­tive of starch sim­i­lar to our fin­ger­nails (Raven and John­son 1999). (Drees and Jack­man, 1998; Ogata, et al., 1998; Raven and John­son, 1999)

  • Sexual Dimorphism
  • female larger
  • Range length
    1 to 2 mm
    0.04 to 0.08 in

De­vel­op­ment

5 to 6 days after being laid, Monomo­rium pharao­nis eggs hatch into lar­vae. Lar­vae grow and de­velop over 22 to 24 days, pass­ing through sev­eral in­stars “growth phases which end with molt­ing). When the lar­vae are ready, they enter the pupal stage to un­dergo com­plete meta­mor­pho­sis that is com­plete 9 to 12 days later. The pupal stage is the most vul­ner­a­ble to en­vi­ron­ment and preda­tors. The pupae are rel­a­tively in­ac­tive, and do not eat. There­fore, adult ants take a total of 38-45 days to fully ma­ture, while an­other 4-5 days are re­quired for sex­ual forms to reach ma­tu­rity.

As the lar­vae grow, they must molt to a larger stage or in­star. Molt­ing is reg­u­lated by the molt­ing hor­mone, ecdysone. This hor­mone is re­leased by a gland lo­cated in the tho­rax, which is stim­u­lated by the "brain hor­mone" pro­duced by neu­rose­cre­tory cells. An­other hor­mone called ju­ve­nile hor­mone is most abun­dant in im­ma­ture stages of the ant, and de­creases with the pass­ing of each stage to­ward adult­hood. (Raven and John­son, 1999)

Re­pro­duc­tion

Pharaoh ants have cop­u­la­tory or­gans for in­ter­nal fer­tilza­tion. After the new queen has mated with at least one male (some­times more) she will store the sperm in her sper­math­eca so that she can use it to fer­til­ize all of her eggs through­out the rest of her life.

Like most ants, sex­ual castes (those ca­pa­ble of re­pro­duc­tion) cop­u­late in a “nup­tial flight”. This is when en­vi­ron­men­tal con­di­tions are fa­vor­able to en­cour­age mat­ing and males and vir­gin queens fly into the air at the same time in order to find mates. After a short while the males die, and the queens lose their wings and find a place to begin her colony. (Raven and John­son, 1999)

After a queen mates, she will found a new colony. This means that she will lay eggs and care for the first brood her­self. After the first gen­er­a­tion ma­ture, they will care for the queen and all fu­ture gen­er­a­tions as the colony grows. In ad­di­tion to the found­ing of a new colony by a newly mated queen, colonies may also “bud”. This is where part of an ex­ist­ing colony car­ries brood to an­other "new" nest­ing site along with a new queen --of­ten a daugh­ter of the par­ent colony’s queen. (Drees and Jack­man, 1998)

After a queen mates, she will found a new colony. This means that she will lay eggs and care for the first brood her­self. After the first gen­er­a­tion ma­ture, the new work­ers will care for the queen and all fu­ture gen­er­a­tions as the colony grows. (Drees and Jack­man, 1998)

Be­hav­ior

Like other hy­menoptera, the pharoah ant has a haplo-diploid ge­netic sys­tem. This means that when the fe­male mates, she stores the sperm. As eggs move down her re­pro­duc­tive ducts, they can ei­ther be fer­til­ized, be­com­ing a diploid fe­male, or not fer­til­ized, be­com­ing a hap­loid male. Be­cause of this un­usual sys­tem, fe­males are more closely re­lated to their sis­ters than they are to their own off­spring. This may ex­plain the pres­ence of fe­male work­ers. The work­ers in­clude food gath­er­ers, "babysit­ters" of the de­vel­op­ing eggs, and guards­men/look outs for the nest.

The nest of a Pharaoh ant con­tains work­ers, queen or queens, and male/fe­male winged ants. The work­ers are fe­male and ster­ile while the males tend to only be winged, with a main func­tion of re­pro­duc­tion. The fe­male and male ants that are winged also pro­vide gen­eral pro­tec­tion for the nest. The queen be­comes a me­chan­i­cal egg layer for her ex­tended life time. Los­ing her wings an av­er­age of five days after mat­ing, the queen quickly set­tles down to egg-lay­ing. (Crozier and Pamilo 1996)

Com­mu­ni­ca­tion and Per­cep­tion

Pharaoh ants com­mu­ni­cate through tough and chem­i­cal mark­ers called pher­e­mones. They are have very good eye sight and can sense vi­bra­tions of po­ten­tial preda­tors or move­ment from their own lar­vae.

Food Habits

The Pharaoh ant is om­niv­o­rous and their broad diet is re­flec­tive of their tol­er­ance of difer­ent habi­tats. Pharaoh ants feed on sweets: jelly, sugar, honey, cakes, and breads. They also enjoy greasy or fatty foods such as pies, but­ter, liver, and bacon. Be­lieve it or not, a pref­er­ence of freshly used med­ical ban­dages at­tracts these ants to hos­pi­tals. These ants may find also their way into your shoe pol­ish. In their nat­ural en­vi­ron­ment, Pharaoh ants may be found en­joy­ing a re­cently de­ceased in­sect such as a cock­roach or a cricket. Pharoah ants use chem­i­cal trails laid down by other work­ers in order to find food. (Drees and Jack­man, 1998)

  • Animal Foods
  • eggs
  • body fluids
  • carrion
  • insects
  • terrestrial non-insect arthropods
  • Plant Foods
  • seeds, grains, and nuts
  • fruit
  • nectar
  • sap or other plant fluids

Pre­da­tion

Since these ants are so small, lit­tle is known about the preda­tors of this species.

Ecosys­tem Roles

Lit­tle is known on the ef­fects these ants have on their na­tive en­vi­ron­ment. In areas where they have been in­tro­duced they are con­sid­ered to be a house­hold pest.

Eco­nomic Im­por­tance for Hu­mans: Pos­i­tive

Monomo­rium pharao­nis re­moves and feeds upon crumbs and bits of food left un­at­tended. Liv­ing with hu­mans, these in­sects do not swarm as other ants, and they limit other house­hold pests such as cock­roaches by eat­ing the left­over, ex­posed food sup­ply.

  • Positive Impacts
  • controls pest population

Eco­nomic Im­por­tance for Hu­mans: Neg­a­tive

Be­cause of their at­trac­tion to soiled ban­dages, hos­pi­tals must limit pa­tient ex­po­sure to this pest. The mi­cro­scopic bac­te­ria that these ants can carry is some­times path­o­genic, in­clud­ing Sal­mo­nella, Pseudomonas, Clostrid­ium, and Staphy­lo­coc­cus. Also Pharaoh ants can annoy home own­ers by con­gre­gat­ing on food and dishes left un­at­tended. (Drees and Jack­man, 1998; Drees and Jack­man, 1998)

Con­ser­va­tion Sta­tus

There is no spe­cial sta­tus for this ant.

Other Com­ments

The Pharoah ant may be con­fused wtih the Thief ant. This ant is sim­i­lar in phys­i­cal char­ac­ter­is­tics, ex­cept has a more yel­low tint to its body. Also, the foods eaten by this ant are sim­i­lar to those of the Pharoah ant. Col­lege cam­puses are ex­cel­lent breed­ing grounds for the Pharoah ant, es­pe­cially the kitchen or dor­mi­to­ries. (Klots and Klots 1959)

Con­trib­u­tors

Sara Di­a­mond (ed­i­tor), An­i­mal Di­ver­sity Web.

Daniel Mor­ris (au­thor), South­west­ern Uni­ver­sity, Stephanie Fab­ri­tius (ed­i­tor), South­west­ern Uni­ver­sity.

Glossary

Australian

Living in Australia, New Zealand, Tasmania, New Guinea and associated islands.

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Ethiopian

living in sub-Saharan Africa (south of 30 degrees north) and Madagascar.

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Nearctic

living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

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Neotropical

living in the southern part of the New World. In other words, Central and South America.

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Palearctic

living in the northern part of the Old World. In otherwords, Europe and Asia and northern Africa.

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agricultural

living in landscapes dominated by human agriculture.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

carrion

flesh of dead animals.

causes disease in humans

an animal which directly causes disease in humans. For example, diseases caused by infection of filarial nematodes (elephantiasis and river blindness).

chaparral

Found in coastal areas between 30 and 40 degrees latitude, in areas with a Mediterranean climate. Vegetation is dominated by stands of dense, spiny shrubs with tough (hard or waxy) evergreen leaves. May be maintained by periodic fire. In South America it includes the scrub ecotone between forest and paramo.

chemical

uses smells or other chemicals to communicate

delayed fertilization

a substantial delay (longer than the minimum time required for sperm to travel to the egg) takes place between copulation and fertilization, used to describe female sperm storage.

desert or dunes

in deserts low (less than 30 cm per year) and unpredictable rainfall results in landscapes dominated by plants and animals adapted to aridity. Vegetation is typically sparse, though spectacular blooms may occur following rain. Deserts can be cold or warm and daily temperates typically fluctuate. In dune areas vegetation is also sparse and conditions are dry. This is because sand does not hold water well so little is available to plants. In dunes near seas and oceans this is compounded by the influence of salt in the air and soil. Salt limits the ability of plants to take up water through their roots.

detritus

particles of organic material from dead and decomposing organisms. Detritus is the result of the activity of decomposers (organisms that decompose organic material).

ectothermic

animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature

eusocial

the condition in which individuals in a group display each of the following three traits: cooperative care of young; some individuals in the group give up reproduction and specialize in care of young; overlap of at least two generations of life stages capable of contributing to colony labor

fertilization

union of egg and spermatozoan

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

internal fertilization

fertilization takes place within the female's body

introduced

referring to animal species that have been transported to and established populations in regions outside of their natural range, usually through human action.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

metamorphosis

A large change in the shape or structure of an animal that happens as the animal grows. In insects, "incomplete metamorphosis" is when young animals are similar to adults and change gradually into the adult form, and "complete metamorphosis" is when there is a profound change between larval and adult forms. Butterflies have complete metamorphosis, grasshoppers have incomplete metamorphosis.

mountains

This terrestrial biome includes summits of high mountains, either without vegetation or covered by low, tundra-like vegetation.

native range

the area in which the animal is naturally found, the region in which it is endemic.

omnivore

an animal that mainly eats all kinds of things, including plants and animals

oriental

found in the oriental region of the world. In other words, India and southeast Asia.

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pheromones

chemicals released into air or water that are detected by and responded to by other animals of the same species

rainforest

rainforests, both temperate and tropical, are dominated by trees often forming a closed canopy with little light reaching the ground. Epiphytes and climbing plants are also abundant. Precipitation is typically not limiting, but may be somewhat seasonal.

scent marks

communicates by producing scents from special gland(s) and placing them on a surface whether others can smell or taste them

scrub forest

scrub forests develop in areas that experience dry seasons.

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

sperm-storing

mature spermatozoa are stored by females following copulation. Male sperm storage also occurs, as sperm are retained in the male epididymes (in mammals) for a period that can, in some cases, extend over several weeks or more, but here we use the term to refer only to sperm storage by females.

stores or caches food

places a food item in a special place to be eaten later. Also called "hoarding"

suburban

living in residential areas on the outskirts of large cities or towns.

tactile

uses touch to communicate

temperate

that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).

terrestrial

Living on the ground.

tropical

the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.

tropical savanna and grassland

A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.

savanna

A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.

temperate grassland

A terrestrial biome found in temperate latitudes (>23.5° N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.

urban

living in cities and large towns, landscapes dominated by human structures and activity.

vibrations

movements of a hard surface that are produced by animals as signals to others

visual

uses sight to communicate

year-round breeding

breeding takes place throughout the year

Ref­er­ences

Crozier, R., P. Pamilo. 1996. Evo­lu­tion of So­cial In­sect Colonies: Sex al­lo­ca­tion and Ken Se­lec­tion. New York, New York: Ox­ford Uni­ver­sity Press Inc..

Drees, B., J. Jack­man. 1998. A feild Guide to Com­mon Texas In­sects. Hous­ton, Texas: Gulf Pub­lish­ing Com­pany.

Green­smiths, Jan­u­ary 2000. "Pharaoh Ants" (On-line). Ac­cessed April 15, 2000 at http://​www.​greensmiths.​com/​pharaoh.​htm.

Grz­imek, B., J. Liebig. 1972. Grz­imek's An­i­mal Life En­cy­clope­cia: Vol­ume 2, In­sects. New York, New York: Van Nos­trand Rein­hold Com­pany.

Howard, L. 1908. The In­sect Book. New York, New York: Dou­ble­day, Page & Com­pany.

Klots, A., E. Klots. 1959. Liv­ing In­sects of the world. Gar­den City, New York: Dou­ble­day & Com­pany Inc..

Ogata, K., M. Ter­ayama, R. Tay­lor. 1998. "Japan­ese Ant Data­base Group" (On-line). Ac­cessed April 14, 2000 at http://​taxa.​soken.​ac.​jp/​ANT.​WWW/​Taxo_​E/​F41107.​html.

Raven, P., G. John­son. 1999. Bi­ol­ogy, 5th Edi­tion. New York, New York: WCB Mc­Graw-Hill.

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Classification

Classification

  • Kingdom Animalia animals
  • Class Insecta insects
  • Order Hymenoptera
  • Family Formicidae ants, fourmis
  • Genus Monomorium
  • Species Monomorium pharaonis pharaoh ant