Fire Ants

Invasive Species of the Galapagos Islands

Wasmannia auropunctata (Roger)

Common name: Little Fire Ant (LFA)Other typical names: albayalde, cocoa tree-ant, hormiguilla, little red fire ant, satanica, small fire ant, West Indian stinging ant.Scientific name: Wasmannia auropunctata (Roger)Classification:

Phylum: ArthropodaClass: InsectaOrder: HymenopteraFamily: FormicidaeSubfamily: Myrmicinae

Identification

The Little Fire Ant is a very slow moving, kind of brownish orange species.The size is about 1.5 mm or 5.5mm long.The ant has a three jointed antennal club, two spines on the posterior dorsal portion of the thorax, and lacks teeth on its clypeus.The W. auropunctata is described as neotropical in its origin.The fire ant is abundant in Central and South America-The date and site of introduction was: Santa Cruz Island, between 1910 and 1920. The first published record was in 1972 by Silberglied.

What are fire ants in the Galapagos Islands?

The Galapagos Islands have five subfamilies, 21 genera and 44 species of ants. 30 of them were introduced to the islands. The Little fire ant, Wasmannia auropunctata and the tropical fire ant, Solenopsis geminata, are considered serious threats to the terrestrial fauna of the islands. (Herrera & Causton 2007 in press) Fire ants sting like bees. Fire ants have a toxic venom that causes a burning sensation. Fire ants also bite causing a lot of pain.Fire ants can be reddish-brown and black.

How were fire ants introduced to the Galapagos Islands?

The small fire ant, Wasmannia auropunctata Roger, is considered the most aggressive species ever introduced to the Galapagos Islands.This species is considered one of the most dangerous invasive species at a global level according to the Invasive Species Global Program.In 1910 and 1920, this species was introduced into the islands. The species originally colonised Santa Cruz Island.In 1988, fire ants ended up on Marchena island.

Ecological Role

The W. auropunctata is an extremely competitive tramp ant species.This ant has generalistc food requirements and hábitat.They live in warm áreas below 4.000 feet elevation.They make nests in cracks, under rocks, potted plantas, leafs, stones ornamental trees and sometimes even sand.They eat invertebrates and parts of plants. They feed on honeydew.

Impact of the fire ants

Fire ants are a serious threat to the fragile ecosystem of the islands.These ants cause a negative impact on the native communities, threatening the reptile and bird populations and damaging plants.The chemical used for killing the fire ants can also affect the other species.When they use the aerial application of the toxic pesticides, they can also affect the birds and the plants.

Control

There are various chemical treatments used to control the fire ants, for example, Amdro or Extinguis.These chemicals or pesticides applications help reduce the population of fire ants.For colinies of fire ants, that live in or around buildings, residual insecticide should be used.When the colinies live in a wall void or wood, you have to inject a dust or aerosal insecticide.

Eradication

In 2000, Marchena island began an eradication programme of the fire ant.The Charles Darwin Foundation is in charge of this programme with the colaboration of the park ranges of the Galapagos National Park.There is a two-phase methodology:A monitoring programme of the fire ants and other communities used the baits sausage, peanut butter, tuna, sweet biscuits. A control programe that used an insecticide AMDRO-hydramethylnon 0.73g/kg- that was dispersed in the infested áreas.

Bibliography

http://www.antweb.org/galapagos.jsphttp://insects.about.com/od/antsbeeswasps/f/What-Are-Fire-Ants.htm http://www.hear.org/galapagos/invasives/topics/management/invertebrates/projects/ants.htmhttp://www.columbia.edu/itc/cerc/danoff-burg/invasion_bio/inv_spp_summ/Wasmannia_auropunctata.htmhttp://www.galapagos.org/conservation/conservationchallenges/