Tramp-ant
Guides
Brachymyrmex brevicornis
Brachymyrmex brevicornis is a species of ant in the family Formicidae, originally described by Emery in 1906. The species is currently recognized as accepted in major taxonomic databases, though some sources list it as a synonym of Brachymyrmex cordemoyi. It belongs to the subfamily Formicinae and tribe Myrmelachistini. The genus Brachymyrmex consists of small, inconspicuous ants commonly known as "rover ants" that are frequently associated with human-modified environments.
Brachymyrmex obscurior
Seaside Rover Ant
Brachymyrmex obscurior is a small ant species in the family Formicidae, commonly known as the Seaside Rover Ant. It is recognized as a globally distributed invasive tramp ant species, particularly prevalent in tropical and subtropical urban environments. The species has been documented in the conterminous United States, Hawaii, and Brazil, among other regions. It is frequently associated with human-modified habitats and is considered part of the community of invasive ant species that dominate urban landscapes in areas such as Florida.
Camponotus sexguttatus
Six-spotted Carpenter Ant
Camponotus sexguttatus is a Neotropical carpenter ant native to South America, Central America, Mexico, and the Caribbean. The species has established invasive populations in Florida, Hawaii, and Arizona, where it has been documented as a 'tramp ant' in urban environments. It belongs to the diverse genus Camponotus, which includes over 1,000 species of wood-nesting ants. Multiple subspecies have been described across its native range.
Linepithema
Linepithema is a genus of small ants in the subfamily Dolichoderinae, comprising approximately 20 described species. The genus is native to the Neotropics, ranging from northern Mexico through the Caribbean to northern Argentina, with species occurring from sea level to 4,000 meters elevation in the Andes. Two species, L. humile (the Argentine ant) and L. iniquum, have been introduced globally through human activity. L. humile is among the most successful invasive ant species worldwide, forming massive supercolonies in Mediterranean-type climates.
Linepithema humile
Argentine ant
Linepithema humile, the Argentine ant, is a highly invasive species native to northern Argentina, Uruguay, Paraguay, Bolivia and southern Brazil. It has become established in Mediterranean climate regions worldwide through human-mediated dispersal. The species forms expansive supercolonies through unicolonial organization, where neighboring colonies cooperate rather than compete. This structure enables rapid population growth and displacement of native ant species. L. humile is considered one of the most ecologically damaging invasive ants globally.
Monomorium floricola
Bicolored Trailing Ant, Flower Ant
Monomorium floricola is a small myrmicine ant native to tropical regions that has become a widespread global invader. Commonly known as the bicolored trailing ant or flower ant, it is frequently transported through human commerce and has established populations across multiple continents. The species is characterized by its diminutive size, polygynous colony structure, and association with human-disturbed habitats. It is recognized as a significant invasive species with potential ecological impacts in tropical biodiversity hotspots.
Monomorium minimum
Monomorium minimum is a small myrmicine ant species documented as an effective predator of mosquito eggs in urban environments. The species has been observed removing 99.4% of Aedes aegypti eggs from experimental containers within 4 days, demonstrating significant potential for biological control of disease-vectoring mosquitoes. As a member of the genus Monomorium, it belongs to a group often referred to as 'tramp ants' associated with human-modified habitats.
Monomorium pharaonis
Pharaoh Ant
Monomorium pharaonis, commonly known as the pharaoh ant, is a small (approximately 2 mm) yellow to light brown invasive ant species of unknown origin that has become one of the most widespread and problematic indoor pest ants globally. It is a highly polygynous, unicolonial species with colonies containing multiple queens, workers, males, and brood. The species exhibits pronounced caste polyphenism with distinct morphologies and behaviors across queens, workers, and males. Pharaoh ants are notorious for infesting hospitals, food service facilities, and residential structures, where they pose significant public health risks as mechanical vectors of pathogens. Their complex social structure, involving multiple reproductives and decentralized nest sites, makes them exceptionally difficult to control using conventional insecticide treatments.
Nylanderia bourbonica
Robust Crazy Ant
Nylanderia bourbonica, commonly known as the Robust Crazy Ant, is a widespread invasive tramp ant species native to tropical regions. It has been introduced to multiple continents including North America, where it is established in Florida and other subtropical areas. The species exhibits characteristic erratic, rapid movement patterns and forms large polygynous colonies. As a generalist forager associated with human-modified environments, it can reach nuisance pest levels in urban settings.
Paratrechina longicornis
Longhorn Crazy Ant, Black Crazy Ant
Paratrechina longicornis, commonly known as the longhorn crazy ant or black crazy ant, is a small dark-colored ant species in the family Formicidae. It is one of the most widely distributed ant species globally, found in nearly every tropical and subtropical location through human-mediated transport. The species exhibits remarkable adaptability to human-modified environments, thriving in urban centers, greenhouses, and buildings even in temperate climates. Its erratic, non-linear movement patterns earned it the common name 'crazy ant'. The species is considered one of the world's worst invasive ant species due to its ecological and economic impacts.
Pheidole hyatti
Hyatt's Big-headed Ant
Pheidole hyatti is a species of big-headed ant in the family Formicidae. Native to the southwestern United States, Mexico, and Guatemala, it has become invasive in Hawaii and possibly established in Panama, Bolivia, and Argentina. The species was described by Emery in 1895 and contains one accepted subspecies, Pheidole hyatti hyatti. As a member of the hyperdiverse genus Pheidole, it exhibits the characteristic worker polymorphism with distinct major and minor worker castes.
Pheidole megacephala
big-headed ant, coastal brown ant, African big-headed ant
Pheidole megacephala is a highly successful invasive ant species native to tropical Africa, considered among the world's worst invasive organisms. It exhibits true worker dimorphism with distinct major and minor worker castes, the former bearing disproportionately large heads used for crushing food. The species forms expansive supercolonies through budding reproduction, enabling rapid territorial expansion. It has spread globally to tropical and subtropical regions, where it aggressively displaces native ant faunas and disrupts ecosystem function through generalist predation and mutualistic associations with sap-sucking insects.
Pheidole navigans
Navigating Big-headed Ant, Wandering Big-headed Ant
Pheidole navigans is a small, dimorphic big-headed ant native to the Neotropics and established as invasive across multiple regions including the southeastern United States, California, Hawaii, Bermuda, Madeira, Tenerife, and Vanuatu. Formerly synonymized with Pheidole flavens, it was restored to full species status in 2015. The species exhibits a dimorphic caste system with major and minor workers, and is characterized by small size, generalist ecology, and flexible nesting habits. Its ecological impacts in invaded regions are currently considered limited.
Pheidole obscurithorax
Large Imported Big-headed Ant
Pheidole obscurithorax is a large, dark, dimorphic ant native to northern Argentina and Paraguay. It was introduced to Mobile, Alabama in the early 1950s and has since spread along an 80-km-wide coastal band between Alabama and Tallahassee, Florida. The species is characterized by worker dimorphism with enlarged-headed majors and has demonstrated rapid population growth in invaded areas, with nest density increasing 6.4-fold over two years in Tallahassee. It coexists with the red imported fire ant (Solenopsis invicta) and appears to have minimal negative impact on native ant communities, being part of a largely exotic ant assemblage adapted to disturbed habitats.
Strumigenys eggersi
Eggers' Pygmy Snapping Ant
Strumigenys eggersi is a Neotropical ant species in the tribe Attini, first described by Emery in 1890. It belongs to a genus characterized by specialized trap-jaw mandibles used for prey capture. The species has been documented as an introduced species outside its native range, with confirmed records from the Philippines and the United States. It is classified as a 'tramp ant,' indicating human-mediated dispersal, though its ecological impacts in introduced regions remain unknown.
Strumigenys rogeri
Roger's Pygmy Snapping Ant
Strumigenys rogeri is a small dacetine ant species first described by Emery in 1890. It is notable for exhibiting thelytokous parthenogenesis in Taiwan, where virgin queens produce female offspring without mating. This reproductive mode, combined with a short development time of approximately 39 days, may contribute to its success as a tramp ant species. The species belongs to a genus of over 850 species characterized by distinctive trap-jaw mandibles.
Tapinoma melanocephalum
Ghost ant
Tapinoma melanocephalum, commonly known as the ghost ant, is a minute ant species recognized by its distinctive bicolored appearance: dark brown head and thorax contrasting with pale, translucent legs, antennae, and gaster. Native to tropical regions of Africa and Asia, it has become a globally distributed "tramp" species through human commerce, establishing populations in greenhouses, heated buildings, and tropical urban environments worldwide. The species is considered a significant household pest, particularly in Florida and Hawaii, where it nests indoors and forages for sweet foods. Recent taxonomic revision has revealed that what was long considered T. melanocephalum actually comprises two cryptic species, with T. pithecorum described as new in 2020.