Fire ant: Difference between revisions
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== Roles == |
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A queen is generally the largest individual in the colony. The primary function of the queen is reproduction; she may live for 6–7 years and produce up to 1,500 eggs per day. Many fire ant colonies will have more than one queen. |
A queen is generally the largest individual in the colony. The primary function of the queen is reproduction; she may live for 6–7 years and produce up to 1,500 eggs per day. Many fire ant colonies will have more than one queen. |
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===Males=== |
===Males=== |
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Revision as of 18:50, 21 May 2009
| Fire ant | |
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| Solenopsis queens and workers | |
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| Genus: | Solenopsis Westwood, 1840
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S. conjurata | |
Fire ants are a variety of stinging ants with over 280 species worldwide. They have several common names including Ginger Ants and Tropical Fire Ants (English), aka-kami-ari (Japanese), Solenopsis (French), and Feuerameise (German).
Appearance
Fire ants can be distinguished from other ants by their copper brown head and body with a darker abdomen. The worker ants are blackish to reddish, and their size varies from 2mm to 6 mm (0.12 in to 0.24 in). These different sizes of the ants can all exist in the same nest.
Solenopsis sp. ants can be identified with three body features - a pedicel with two nodes, an unarmed propodium, and antennae with 10 segments and a two segmented club.
Behaviour
A typical fire ant colony produces large mounds in open areas, and feeds mostly on young plants, seeds, and sometimes crickets. Fire ants often attack small animals and can kill them. Unlike many other ants, which bite and then spray acid on the wound, fire ants only bite to get a grip and then sting (from the abdomen) and inject a toxic alkaloid venom called Solenopsin, a compound from the class of piperidines. For humans, this is a painful sting, causing a burning sensation—hence the name fire ant—with the after effects being potentially deadly to sensitive individuals. The venom is both insecticidal and antibiotic. Researchers have proposed that nurse workers may spray their brood to protect them from microorganisms[citation needed]
Fire ants nest in soil, often near moist areas such as river banks, pond edges, watered lawns and highway edges. Usually the nest will not be visible as it will be built under objects such as timber, logs, rocks, pavers, bricks, etc. If there is no cover for nesting, dome-shaped mounds will be constructed, but this is usually only found in open spaces such as fields, parks and lawns. These mounds can reach heights of 40 cm (15.7 in)[citation needed]
Colonies are founded by small groups of queens or single queens. Even if only one queen survives, within a month or so the colony can expand to thousands of individuals. Some colonies may be polygynous (having multiple queens per nest).[1]
Roles
A queen is generally the largest individual in the colony. The primary function of the queen is reproduction; she may live for 6–7 years and produce up to 1,500 eggs per day. Many fire ant colonies will have more than one queen.
Males
Males mate with the queen ant for the purpose of producing eggs. Shortly following, however, the male ants usually die.
Workers
The workers are sterile females who build and repair the nest, care for the young, defend the nest, and feed both young and adult ants. The worker ants also go find supplies to build the nest.
Introduced species
Although most fire ant species do not bother people and are not invasive due to biological factors, Solenopsis invicta, commonly known as the Red imported fire ant (or RIFA) is an invasive pest in many areas of the world, notably the United States, Australia, the Philippines, China and Taiwan. The RIFA was accidentally introduced into the United States due to a South American cargo ship coming to an Alabama port in 1918, but now infests the majority of the Southern and Southwestern United States.
In the US, the FDA estimates that more than US$5 billion is spent annually on medical treatment, damage, and control in RIFA-infested areas. Furthermore, the ants cause approximately US$750 million in damage annually to agricultural assets, including veterinarian bills and livestock loss as well as crop loss.[2] Since September 2004, Taiwan has been seriously affected by the red fire ant.
The US, Taiwan and Australia all have ongoing national efforts to control or eradicate the species, but, other than Australia, none have been especially effective. In Australia an intensive program costing A$175 million has, at February 2007, eradicated 99% of fire ants from the sole infestation occurring in South East Queensland.
Symptoms and first aid
The venom of a fire ant sting causes stinging and swells into a bump. This can cause much pain and irritation at times, especially when stung repeatedly by several at once. The bump often forms into a white pustule, which is at risk of becoming infected if scratched; however, if left alone, it will usually go down within a few days. The pustules are unattractive and uncomfortable while active and, if the sting sites become infected, can turn into scars. Additionally, some people are allergic to the venom and, as with many allergies, may experience anaphylaxis, which requires emergency treatment.[3] An antihistamine or topical corticosteroids may help reduce the itching.
First aid for fire ant bites includes external treatments and oral medicines.
- External treatments: a topical steroid cream (hydrocortisone), or one containing aloe vera. Also, regular toothpaste can be a quick and simple relief.
- Oral medicines: antihistamines.
Patients who experience severe allergic reactions to fire ant insect stings should visit a doctor or hospital immediately upon contact as these reactions can result in death. These more severe reactions include severe chest pain, nausea, severe sweating, loss of breath, serious swelling, or slurred speech.[4]
Other names
In Spanish, fire ants are known as hormiga colorada/roja (red ant) or hormiga brava (fierce ant). In Puerto Rico there is a native, very small and slow-moving kind of fire ant called abayarde. In Portuguese, they are called formiga de fogo (fire ant) and formiga lava-pé (wash foot ant).
Natural predators
Phorid flies. Phoridae are a family of small, hump-backed flies resembling fruit flies. The genus Pseudacteon, or ant-decapitating fly, of which 110 species have been documented, is a parasitoid of the ant in South America. Members of Pseudacteon reproduce by laying eggs in the thorax of the ant. The first instar larvae migrates to the head. The larvae develop by feeding on the hemolymph, muscle tissue, and nervous tissue in the head. After about two weeks, they cause the ant's head to fall off by releasing an enzyme that dissolves the membrane attaching the ant's head to its body. The fly pupates in the detached head capsule, requiring a further two weeks before emerging. The phorid flies have been widely introduced throughout the U. S. Southeast, starting with Travis, Brazos, and Dallas counties in Texas, as well as Mobile, Alabama, where the ants first entered North America.
Spike in US Population
Recently there has been a large spike in the Fire Ant population of the southern United States[5]. Enviornmentalists have predicted that before next April the Fire Ant Population will have increased by nearly 40% in the United States.[6] The Ants are believed to be coming from Mexico and contain a much more poisonous venom than other fire ants, thus causing many states to start emergency programs to destroy fire ant colonies before they spread.[7]
Species
This species list is incomplete.
See also
References
- ^ Colonies in Florida dissected and observed with greater than 5 queens
- ^ McDonald, Maggie (2006). "Reds Under Your Feet (interview with Robert Vander Meer)". New Scientist. 189 (2538): 50.
{{cite journal}}: Unknown parameter|month=ignored (help); Unknown parameter|quotes=ignored (help) - ^ deShazo RD, Butcher BT, Banks WA (1990). "Reactions to the stings of the imported fire ant". N. Engl. J. Med. 323 (7): 462–6. PMID 2197555.
{{cite journal}}: CS1 maint: multiple names: authors list (link) - ^ "Insects and Scorpions". The National Institute for Occupational Safety and Health. 2008-10-22. Retrieved 2008-11-04.
- ^ FoxNews.com
- ^ New York Times
- ^ FoxNews.com
- Bert Hölldobler and Edward O. Wilson (1990). The Ants. Cambridge: Belknap Press of Harvard University Press. ISBN 3-540-52092-9.
- "Areawide suppression of Fire Ants using baits and Biological Control" (PDF). USDA. 2003. Retrieved 2006-10-25.
{{cite journal}}: Cite journal requires|journal=(help) Details use of Phorid flies - ITIS: Solenopsis species list (2001)
- Treatment of Fire Ant Bites
- Medical Treatment of Fire Ant Bites
External links
