Regular FINIA followers will know that we have been closely watching the yellow crazy ant (Anoplolepis gracilipes) situation on the mainland for many years.

Yellow crazy ants were first recorded in Hervey Bay near the Urangan boat harbour in early 2005. After attempts to eradicate this 77 Ha infestation, populations of the ants have continued to be monitored by Fraser Coast Regional Council near Booral (Hervey Bay) and Maryborough.

Considered to be one of the top 100 ‘World’s Worst invasive species’ by the IUCN, yellow crazy ants made their way into Australia through our ports. After first arriving on Christmas Island sometime before 1934, the ants have established in Queensland, the Northern Territory and NSW.

Yellow crazy ants do not bite. Instead, the highly aggressive species sprays formic acid to blind and kill their prey. They feed on a range of animals to access protein, but they also obtain carbohydrates from plant nectar and honeydew from scale insects; and although they’re tiny, they can swarm in great numbers, killing much larger animals like lizards, frogs, small mammals, turtle hatchlings and bird chicks and reshaping entire ecosystems. 

For K’gari, they pose a significant threat to our ground-dwelling and nesting birds like the Black-breasted button-quail (Mur’rindum) and Ground parrot, but other threatened species including water mouse, long-nosed potoroo, three-toed snake-tooth skink, common death adder, blind snake, acid frogs and nesting loggerhead and green turtles. 

The ants were recently recorded by Fraser Coast Council in new locations. In Hervey Bay, the most recent finds were at the dog park on Vista St, Urangan which has spread from an industrial block on Becks Road, and an area around the entrance statement into Maryborough and Ellengowan Street, which has spread from the Cicada Lane site. An earlier site in Maryborough at Anzac Park around Ululah Lagoons has also spread across Alice St into EB Uhr Park.

While these yellow crazy ant colonies have been treated and are included in a biannual management program, full eradication by the Council is unlikely for now. The council has a long-term plan to tackle the problem but lacks state or federal funding to support its efforts.

The increase in colonies is a concern. Most ant species build colonies with a single queen.  Yellow crazy ants can build super colonies with multiple queens (up to 300) and multiple nests, some of which are the largest of any ant species worldwide extending over 150 hectares, with densities of 20 million ants per hectare recorded on Christmas Island.

Unless there is an intervention, the outlook for K’gari, the island’s ecosystems, species and tourism industry if (when) the ants make it across the water is dire. The Queensland Government’s Invasive Animal Risk Assessment (2016) for yellow crazy ants states that “Habitats most at risk are offshore islands with dense forest, monsoon forest/rainforest and plantations along the tropical east coast (generally shady, moist habitats).”

We are asking the Fraser Coast community and visitors to K’gari to be vigilant and help us to watch out for yellow crazy ants. If you find a potential nest on your property, please contact Council’s customer service team on 1300 79 49 29.

Compiled by Sue Sargent, FINIA with input from Fraser Coast Regional Council