YELLOW CRAZY ANTS ON CHRISTMAS ISLAND
Yellow crazy ant has unusually long leg and antennae. The researchers detected one super colony of Anoplolepsis gracilipes in 1989 on a high terrace above the Grotto (3 ) . The super colonies were again detected by researchers from Melbourne’ Monash University in 1997. The researchers were investigating the role of red land crab (Geocarcoidea natalis) on the Christmas Island ecosystem (4).
The Yellow crazy ant killed and displaced approximately ten(3) to twenty (3) millions of crabs on the rainforest floor. Crabs are keystone species of the rainforest. Anoplolepsis gracilipes consumed indigenous crabs and also occupied their burrows. They use formic acid to defend and to suppress their prey such as coconut crabs and reptiles (3 ).
The absences of crabs lead to the growth of seedling and spread of weeds on the Christmas Island. The population of Dendrocnide peltata began to increase and closed tracks which were used by people during their visitation on the Island (3) . At about ninety percent of the trees and shrubs were swarmed with sooty mould which resulted to the extensive canopy dieback. The population of indigenous birds, reptiles and mammals were also reduced. Studies indicated that the predation of immature Fregata andrewsi by crazy ant will result to decline of its population by eighty percent in the next thirty years (5). Anoplolepsis gracilipes is a dangerous agricultural pest (2).
The Park staff and experts struggled to find an appropriate method of baiting ants in 1999 and 2000. The amount of $1.5 from Natural Heritage trust was used to control crazy ants in 2000-2001(5). The successful eradication campaign took place in September 2002 and aerial baiting was used followed by continuous monitoring (5).
1. O’Dowd. 2006. Anoplolepis gracilipes (insect) [Online]. [cited 2007 Jan 24] Available from:
2. Wikepedia Contributors. Crazy ant [Online] Wikepedia,The free Encyclopedia; 2007 Jan 12; 03:23 UTC [ cited 2007 January 24]. Available from: http://en.wikipedia.org/wiki/Yellow_crazy_ant
3. DEH. Yellow crazy. [Online]. [cited 2007 Jan 24] Available from: http://www.deh.gov.au/parks/christmas/fauna/crazy.htm
4. Kingsley D. 2003. Crazy ant lose battle, but still at war. [Online]. [cited 2007 Jan 24]
5. Sue Matthews. 2004. Tropical Asia invaded: The growing danger of invasive alien species Global Invasive Species Programme [Online]. [cited 2007 Jan 24] Available from: