Galapagos Species Database

Taxon category: Accepted

Origin: Introduced - established

Year of first record: 1905

Mode of introduction: Accidental

Introduction Pathway: Contaminant

Subpathway: Contaminant on plants (inc. seeds and plant associated material)

Introduced status: Naturalized

Invasive status: Invasive

Impact in Galapagos: Wasmannia auropunctata has had a wide-ranging impact on biodiversity in the Galápagos, in particular to native invertebrates. It also negatively affects the nesting activities and young of reptiles and birds and its painful sting makes it a significant pest to farmers and conservation workers. Additionally, Wasmannia auropunctata aids the build up and spread of populations of the cottony cushion scale (Icerya purchasi) and other invasive scale insects, where honeydew produced by this scale insect is exchanged for transportation and protection from predators.

Impact elsewhere: It has been listed as one of the 100 most invasive species in the world by "Invasive Species Specialist Group of the World Conservation Union (IUCN)". Wasmannia auropunctata has had a direct negative impact on many animals, both vertebrates and invertebrates. It is responsible for reducing the diversity of invertebrate species on many Pacific islands. In New Caledonia it has impacted small reptiles. In Gabon, Africa and the Pacific islands it is known to cause blindness and clouded corneas in domestic animals and other vertebrates. Because of its sting it is a nuisance to farmers. It is considered the most aggressive species that has been introduced to the Pacific islands.

Control History in Galapagos: Wasmannia auropunctata was successfully eradicated in 1990 from 3 ha. on Santa Fe island using Amdro®. This species was also eradicated from an area of 21 ha on Marchena island using Amdro ®. The success of this program was due, in part, to the intensive monitoring activities performed after the poison bait was applied. This was done by placing sticks painted with peanut butter in a grid 3m apart in the infested area. The results of studies in the laboratory and the field in Galápagos, as well as in other parts of the world, suggest that Hydramethylnon is effective and has minimal impact on the environment. However, it does affect other species of ants and other invertebrate groups and because of this, nontarget risks should be evaluated before initiating a control program.

Control methods elsewhere: The suggested control method is control using a pesticide that contains hydramethylnon (e.g. Amdro® y Siege Pro®). Ants collect the poison and transport it back to their nest where it kills the entire colony.

Known Pest elsewhere: Western Africa, North and South America, Caribbean, Pacific Islands

Prevention options: Inspect all fruits, vegetables, and food for ants. Prohibit movement of soil between islands or regions.

Preference for an altitude zone in Galapagos: Dry zone - humid zone

Habitat preferences: Little red fire ants inhabit disturbed areas, forested areas, and riparian (alongside a river or stream) habitats. They can occupy natural areas as well as disturbed habitats such as farmland and human habitations. Nests can be found on the ground as well as up in trees.

Feeding preferences: Wasmannia auropunctata is primarily known as a predator of invertebrates, but a portion of its diet consists of the sugary substances excreted by Homoptera (honey dew).

Trophic role: Omnivorous

Persistence mechanisms: Attributes that make Wasmannia auropunctata a successful invader include its adaptability to a wide range of habitats, polyphagous feeding habits, high interspecific aggression, and lack of intraspecific aggression which leads to unicoloniality. Colonies are polygynous, increasing the likelihood that small numbers of ants that are split off from the colony, or are transported by man, are able to found a new colony.

Reproduction mode: Both sexual and asexual

Reproductive biology: Because colonies have multiple queens (polygyny), any transported colony fragment containing at least one queen can found a new population at its destination. Wasmannia auropunctata is thought to spread primarily by “budding” off of groups of workers accompanied on foot by inseminated queens. A single nest of little fire ants may contain several wingless reproducing queens, many workers, pupae, larvae, and eggs. The little fire ant nests under decomposing wood and leaves, stones, and in trees. The little fire ant is highly adaptable, nesting in both open and shaded areas, and thrives in both moist or xeric conditions. Nest migration is frequent. This species has two types of reproductive systems: 1) Sexual reproduction of workers and females (typical form of reproduction) and males by parthenogenesis; 2) males and females can reproduce independently by clonation, and workers reproduce sexually. Clonation is typically observed in human or disturbed habitats, whereas sexual populations typically occur in natural habitats. Development from egg to adult lasts an average of 35 days (egg: 9 days; larvae: 17 days; pupae: 11-12 days).

Distribution origin: Central and South America

Dispersal propagule: Workers typically accompany the queen to establish a new colony (budding) and this is done on foot. The only place where mating flights have been observed is in Puerto Rico, which is possibly part of its native range. Ant colonies are easily transported on fruits (e.g. transportation of a colony of ants has been observed on a pineapple), vegetables and soil, and the growth of trade between countries has helped its colonization in many parts of the world.

Natural enemies: Orasema minutissima (Hymenoptera: Eucharitidae) - Neotropics

Associated species in Galapagos: Honeydew-producing scale insects, e.g. Icerya purchasi.

Map of specimen collection localities or observation records for this species in our collections database.

Distribution: Albany, Bainbridge #1, Baltra, Bowditch South, Champion, Cousin, Eden, Española, Floreana, Gran Felipe, Isabela, Mao, Marchena, Pinzon, Rabida, Santiago, San Cristobal, Santa Cruz, Seymour Norte, Santa Fé, Tortuga

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