Please click on AntWeb: Anoplolepis gracilipes for more images and assistance with identification. The AntWeb image comparison tool lets you compare images of ants at the subfamily, genus, species or specimen level. You may also specify which types of images you would like to compare: head, profile, dorsal, or label.
Please see PaDIL (Pests and Diseases Image Library) Species Content Page Ants: Yellow crazy ant for high quality diagnostic and overview images.

Please follow this link for a fully illustrated Lucid key to common invasive ants [Hymenoptera: Formicidae] of the Pacific Island region [requires the most recent version of Java installed]. The factsheet on Anoplolepis gracilipes contains an overview, diagnostic features, comparision charts, images, nomenclature and links. (Sarnat, 2008)

Note that it should not to be confused with the similarly named crazy ant (Paratrechina longicornis) and that most literature on A. gracilipes is under its synonym (A. longipes).

The yellow crazy ant has been known to successfully colonise a variety of agricultural systems, including cinnamon, citrus and coffee crops and coconut plantations (Haines and Haines 1978, Van Der Goot 1916, in Holway et al. 2002; O’Dowd et al. 1999) and on banana, rambutan, mango, durian, sugarcane and langsat (Jochen Drescher pers.comm May 2010) . In agricultural regions it is typically found nesting at the base, or even in the crown, of crop plants. For example, on New Guinea it nests in the crowns of coconut trees, feeding off honeydew-producing scale insects and palm flower nectar (Young 1996, in O’Dowd et al. 1999).

A. gracilipes is also capable of invading undisturbed habitats as in the case of the drier monsoon forests on Christmas Island (Indian Ocean), where the yellow crazy ant experienced a population explosion and thrives in (previously) undisturbed native forest habitats (CBD, 2003); it is however not known to enter lowland rainforest or submontane rainforest (Jochen Drescher pers.comm May 2010). The nesting requirements of the ant are general and it often nests under leaf litter or in cracks and crevices (Lewis et al. 1976, Rao and Veeresh 1991, in O’Dowd et al. 1999). On Christmas Island, the yellow crazy ant takes advantage of crab burrows, the woody debris of the forest floor, tree hollows and epiphytes and the hollows created at the base of palm leaves (O’Dowd et al. 1999).

In addition to protein-rich foods A. gracilipes may rely heavily on carbohydrate-rich nutrient sources, such as plant nectar or honeydew-producing scale insects (especially insects in the Homoptera genus). In the Seychelles, the quantity of honeydew in a 2.5mg worker is estimated to be up to 50% (Haines et al. 1994 in O’Dowd et al. 1999). The presence of Homoptera insects may be so important that it may limit population growth. For example, in cocoa plantations in Papua New Guinea Homoptera insect populations are thought to be necessary to support and sustain A. gracilipes colonies (Holway et al. 2002).

Please follow this link for more details on the impacts of yellow crazy ants on biodiversity.

For a summary of the general impacts of invasive ants, such as their affect on mutualistic relations, the competitive pressure they impose on native ants and the effect they may have on vulnerable ecosystems please read this document: invasive ants impacts compiled by the ISSG.

A detailed pest risk assessment for the eight species ranked as having the highest potential risk to New Zealand was prepared as part of 'The Invasive Ant Risk Assessment Project', \r\nHarris et al. 2005., for Biosecurity New Zealand by Landcare Research. Anoplolepis gracilipes scored as a high-risk threat to New Zealand. The Invasive ant risk assessment for A. gracilipes can be viewed at Anoplolepis gracilipes risk assessment. Please see Anoplolepis gracilipes information sheet for more information on biology, distribution, pest status and control technologies. \r\n

Chemical: The toxic principles in ant baits include the so-called “stomach” poisons, hydramethylnon (Maxforce, Amdro), sulfuramid and sodium tetraborate decahydrate (Borax). Insect Growth Regulators (IGRs) disrupt development and include compounds such as methoprene and fenoxycarb. Stomach poisons work relatively fast compared to IGRs, but may sometimes work too quickly, eliminating workers before the insecticide can be distributed throughout the entire colony. One promising approach is to use pheromones (compounds produced by a species that regulate their own behaviour) as “biopesticides” to disrupt the reproduction by the queen (O’Dowd et al. 1999). Baits should be designed with the foraging strategies of the specific ant species in mind. Determining the preferred size, type and dispersal pattern of the bait is an important step. Nesting, foraging and behavioural traits of the ant should all be taken into consideration. The use of appropriately designed baits is needed to reduce the cost of toxin use to native ant populations and non-target fauna (McGlynn, 1999).

Please follow this link for more detailed information on the management of the yellow crazy ant compiled by the ISSG.