Yellow crazy ant
From Wikipedia, the free encyclopedia
- There is also a different genus of ant called "crazy ants", Paratrechina.
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| Anoplolepis gracilipes F. Smith, 1857 |
The yellow crazy ant (Anoplolepis gracilipes) is a species of ant introduced accidentally to northern Australia and Christmas Island in the Indian Ocean, becoming a pest in both locations. The native range is not known exactly, although authors have speculated its origin as West Africa, India, or China [1].
The species is currently known from the following locations
- Australia
- American Samoa
- Christmas Island
- Cocos Islands
- Cook Islands
- Europe and Asia
- French Polynesia
- Guam
- Hong Kong
- India
- Indonesia
- Japan
- Malaysia
- Marshall Islands
- Mauritius
- Myanmar
- Papua New Guinea
- Solomon Islands
- Taiwan
- Thailand
- Tonga
- United States of America
The crazy ant is among the 100 most destructive invasive species. They take advantage of their new environments by nesting in anything, from the crowns of crop plants to the hollows of native palm trees. Their introduction to a new ecosystem has dramatic consequences. Among them is the pressure they place on native ant species.
It is a particular problem on Christmas Island [2]. Instead of forming colonies with a single queen, it now forms supercolonies with several queens which cooperate rather than fight. This aggressive insect has devastated the wildlife of the island. Using formic acid it will overpower sizeable creatures like reptiles and coconut crabs and has killed 10-20 million Christmas Island red crabs. Seedlings that would normally have been devoured by the crabs grow unmolested, noticeably changing the appearance of the affected forests. In addition, the ants protect scale insects that are harmful to plant life. These ants harvest scale insects that suck sap from native trees and convert it into irresistible honeydew on which the ants feed. Thus the scale insect populations explode, increasing the cover of honeydew on native trees, which in turn get infected with molds and die. There are also problems for Christmas Island's red land crabs, which have fed on decaying matter in the island's forests before the ants arrived. The crabs stand no chance against the formic acid spray of the ants. If the crab goes extinct, then the ecology of the island would falter as well. The ant also threatens the survival of many of Christmas Island's native birds, reptiles, and mammals. The crazy ant has also become a serious agricultural pest. So far chemicals and other preventative measures have been used to control them.
It is estimated that the population of Christmas Island Frigatebird (Fregata andrewsi) will decline by 80% in the next 30 years due to predation of the young by Crazy Ants; however, an aerial spraying procedure seems to have had remarkably effective results in controlling the ants.
The name "crazy ant" derives from the ant's foraging technique, involving fast movements with many changes in direction, which becomes especially frantic when it is disturbed.
