They may be small, but don’t be fooled, invasive ants are some of the world’s worst pests. These invasive ants can have a huge impact on our environment, economy, and way of life. Hundreds of millions of dollars are being spent in Australia on ant eradications and control because of their potential for devastating harm to wildlife, infrastructure, industry, and even human health. There are plenty of other ant species that are far too established to be removed. They are the gift that keeps on giving in terms of negative impact to WA now, and for future generations.
Three highly invasive ant species - the red imported fire ant, browsing ant, and African black sugar ant are all trying to gain a foothold into Western Australia. Luckily a crack team of highly trained ant surveillance officers from the WA Department of Primary Industries and Regional Development are on the case.
The invasive ant team are currently conducting surveillance, tracing and treatment activities at residential and commercial properties as well as parklands and disposal sites around Perth and regional areas of WA with the sole purpose of finding and eradicating these ants from our great State.
The department has been engaging and working alongside various pest control teams to treat all three species in suburbs from Bayswater in the north, east to Maida Vale, and East Rockingham in the south.
The department first detected browsing ant (Lepisiota frauenfeldi) in 2013 at the Perth Airport. Since then, nine other infested areas were detected, all of which have been successfully treated to eradication. The team has searched far and wide across the state from Kununurra in the far north to Esperance in the south. Industries and sites considered at risk of moving or harbouring the ant have been searched, including transportation industries, container parks, waste facilities, caravan parks, mine sites, nurseries. The department continues to monitor these and other sites all over WA.
While monitoring for browsing ant, the team detected one of the world’s most serious and invasive pests, the red imported fire ant (Solenopsis invicta) in the Fremantle Port area in November 2019. Luckily, the red imported fire ant was detected early and significant surveillance and contact tracing undertaken in the past two years have not located any additional colonies.
In what felt like déjà vu, WA’s latest invasive ant species, the African black sugar ant (Lepisiota incisa), was detected in January 2020 at the Fremantle Port during routine ant surveillance. This discovery was particularly interesting because, not only was this the first time the ant had been detected in Australia, but it was also not known to be invasive anywhere else in the world. Consequently, in addition to surveillance, the team has had to conduct research to find out what makes them tick and invade where they do as very little was known about them.
All three species of ant have been found mainly in commercial-type premises. Interestingly, the African black sugar ant is the only one that seems to love living in bushland, and happily climbs trees. In fact, their tendency to climb finds them in the rafters and ceiling areas of infested buildings.
Pest control companies have been engaged by the department to help treat many of the infested premises. The department primarily uses fipronil, but have also deployed bifenthrin, chlorpyriphos, and permethrin. In general, the eradication programs utilise spray treatments, but in ecologically sensitive areas, other delivery systems such as hydrogels are used.
In addition to surveillance, the department continues to test and develop baits and bait delivery systems. For example, the department developed the technology behind commercially available paste baits such as Vanquish Pro, a fipronil-based product with protein, fats, and carbohydrates in the matrix.
Early detection and identification are critical to achieving successful control of invasive ants and they can be challenging to positively identify with the naked eye. Pest managers are encouraged to report any unusual ant sightings so that scientists can make an expert identification.
The department offers a longstanding free identification, reporting and information service for unusual pests, diseases or weeds discovered in Western Australia. The Pest and Disease Information Service (PaDIS) answers about 7,500 queries per year from the general public and industry, with ants making up 15-20% of these.
More information and fact sheets on invasive ant species are available on the department’s website.
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