Argentine ant
3193996
223163057
2008-07-02T21:04:50Z
71.63.212.196
/* Description */
{{Expert-verify|date=May 2008}}
{{Taxobox
| name = Argentine ant
| status = Secure
| image = Argentine ant.jpg
| image_width = 250px
| regnum = [[Animal]]ia
| phylum = [[Arthropod]]a
| classis = [[Insect]]a
| ordo = [[Hymenoptera]]
| subordo = [[Apocrita]]
| familia = [[Ant|Formicidae]]
| subfamilia = [[Dolichoderinae]]
| tribus = [[Dolichoderini]]
| genus = ''[[Linepithema]]''
| species = '''''L. humile'''''
| binomial = ''Linepithema humile''
| binomial_authority = Mayr, 1868
}}
The '''Argentine ant''' (''Linepithema humile'', formerly ''Iridomyrmex humilis'') is a tiny dark [[ant]] native to northern [[Argentina]], [[Uruguay]], [[Paraguay]], and southern [[Brazil]]. The species has been inadvertently introduced by humans to many other areas of the world, such as [[South Africa]], [[New Zealand]], [[Japan]], [[Easter Island]], [[Australia]], [[Hawaii]], [[Europe]], and the [[United States]]. They have many locally used common names such as grease ants.
== Description ==
The worker ants are only about 3 mm (1/8th inch) long and can easily squeeze through cracks and holes no more than 1 mm (0.040 inch) in size. Queens are two to four times the length of workers. These tiny ants will set up quarters in the ground, in cracks in concrete walls, in spaces between boards and timbers, even among belongings in human dwellings.
German entomologist Dr.[[Gustav L. Mayr]] identified the first specimens of ''Hypoclinea humilis'' in the vicinity of [[Buenos Aires]], [[Argentina]] in 1866. This species was shortly transferred to the genus ''[[Iridomyrmex]]'', and finally to ''Linepithema'' in the early 1990s.
== Behavior ==
In its introduced range, the Argentine ant often displaces most or all native ants. This can, in turn, imperil other species in the ecosystem, such as native plants that depend on native ants for seed dispersal, or lizards that depend on native ants for food. Argentine ants also cause problems in agricultural areas by protecting plant pests, such as [[aphids]] and [[scale insects]], from predators and parasitoids. In return for this protection, the ants receive a sweet excretion, known as "honeydew". Thus, when Argentine ants invade an agricultural area, the population densities of these plant parasites increase, and so too does the damage they cause to crops.
They have been extraordinarily successful, in part, because different nests of the Argentine ants do not attack or compete with each other, unlike most other species of ant. In their introduced range, their [[genetics|genetic]] makeup is so uniform that individuals from one nest can mingle in a neighboring nest without being attacked. Thus, in most of their introduced range they form "supercolonies". {{Fact|date=May 2008}} In contrast, native populations are more genetically diverse, genetically differentiated (among colonies and across space), and form colonies that are much smaller than the supercolonies that dominate the introduced range. Argentine ants in their native [[South America]] also co-exist with many other species of ants (including, in some places, another damaging invasive ant, the [[Red imported fire ant|red imported fire ant]]), and do not attain the high population densities that characterize introduced populations.<ref>http://ucsdnews.ucsd.edu/newsrel/science/mcants.htm "Success of Introduced Argentine Ants Tied to Reduced Genetic Variation," University of California, San Diego</ref>
[[Image:AntsEatWireSM.JPG|thumb|350px|Argentine ants around circuitry.]]
As can be seen in this photo...
They are attracted by electrical currents{{Fact|date=January 2008}} and are known to have caused damage to air conditioners, heat pumps, telephone junction boxes, traffic lights, gasoline pumps, and so on. When they become lodged or [[electric shock|electrocuted]] between the contacts of [[relay]]s, it damages the contacts and causes the equipment controlled by the relay to malfunction.
== Pest control ==
{{howto}}
[[Image:Argentine ants accessing trap.JPG|thumb|350px|Argentine ants accessing a commercial trap commonly available in the [[United States]]. Within two days of this photograph, the ant colony appeared to have destroyed and had ceased to access the five traps which had been placed.]]Argentine ants are a common household pest, often entering structures in search of food or water (particularly during dry or hot weather), or to escape flooded nests during periods of heavy rainfall. Argentine ant colonies almost invariably have many reproductive queens, as many as eight for every 1,000 workers, so eliminating a single queen does not stop the colony's ability to breed. When they invade a kitchen, it is not uncommon to see two or three queens foraging along with the workers.
Due to their nesting behavior and presence of numerous queens in each colony, it is generally impractical to spray Argentine ants with pesticides or to use boiling water as with mound building ants. Indeed, spraying with [[pesticide]]s will stimulate increased egg-laying by the queens, compounding the problem. Pest control usually requires exploiting their omnivorous dietary habits. They prefer sweet foods such as the honeydew produced by aphids and mealybugs[http://www.rosepestcontrol.com/pages/argentine_ant/42.php]. The most effective control is through use of slow-acting [[poison]] bait, which will be carried back to the nest by the workers, eventually killing all the individuals, including the queens. It may take four to five days to eradicate a colony in this manner. An effective homemade recipe<ref>[http://www.morganhilltimes.com Morgan Hill Times], Friday, [[December 27]], [[2002]] The recipe is scaled down from an article by Keith Muruoka. The original formula called for 4 teaspoons boric acid powder, 3 cups of water and 1 cup of granulated sugar.</ref> consists of a solution of granulated white table [[sugar]] and [[boric acid]], placed in a shallow dish in the area being invaded:
:1/4 teaspoon boric acid powder
:3 tablespoons water
:1 tablespoon sugar
The boric acid will dissolve only if the water is hot, or one can mix the ingredients cold, then place the container in a microwave oven to bring the water to [[boiling]] temperature. When mixed in small quantities, the solution can be stored in a dropper bottle and dispensed as needed to replenish the bait dish. Although the solution isn't particularly hazardous when used in small quantities as described here, the bait dish should be placed out of reach of pets and children.
This formula works by [[desiccation]] and laceration. The solution begins to draw water from the ant's body, causing slow [[dehydration]]. Also, as the ants or their [[larva]]e transpire water, the solution becomes more concentrated, causing the boric acid to [[crystal]]lize and lacerate the [[gastrointestinal tract|digestive tract]].
In areas where the use of liquids or poisons are not desirable, Argentine ants may be repelled by ordinary talcum powder (baby powder) which contains [[talc]]. The powder does not appear to kill the ants, but they will try to avoid it after contact.
Researchers from the [[University of California, Irvine]], have developed a way to use the scent of Argentine ants against them.<ref>[http://sfgate.com/cgi-bin/article.cgi?f=/c/a/2006/09/15/BAG75L6BJK1.DTL Ants' own chemical may control them]</ref> The [[exoskeleton]]s of the ants are covered with a [[hydrocarbon]]-laced secretion. They made a compound that is different, but similar, to the one that coats the ants. If the chemical is applied to an ant, the other members of the colony will kill it. The success of the chemical for controlling Argentine ants will depend on the cost, the ease of application, [[toxicity]] to non-target organisms and the frequency of reapplication. The chemical may work best in combination with other methods.
== References ==
{{reflist}}
== External links ==
* [http://www.insecta-inspecta.com/ants/argentine Insecta Inspecta World - Argentine Ants]
[[Category:Invasive animal species]]
[[Category:Ants]]
[[cs:Mravenec argentinský]]
[[es:Linepithema humile]]
[[fr:Linepithema humile]]
[[ja:アルゼンチンアリ]]
[[pt:Formiga-argentina]]