Browsing ant in the Northern Territory, Queensland and Western Australia
National browsing ant (Lepisiota frauenfeldi) eradication programs are continuing in the Northern Territory (NT), Queensland (QLD) and Western Australia (WA).
Browsing ant is exotic to Australia and is a serious environmental pest.
Current situation in the NT
Browsing ant was first detected in the NT in June 2015 at Darwin’s seaport. A total of 23 infested premises have been identified since 2015, 16 of which have been resolved. Six infested premises remain in the greater Darwin area and are expected to be resolved by early 2021.
One infested premises was detected at Jabiru in September 2020. This was a direct trace from the most recent infested premises in Darwin. Surveillance and treatment activities are underway at the Jabiru premises.
Once further surveillance and tracing has been completed, the National Biosecurity Management Consultative Committee will convene to determine if the significant detection at Jabiru has compromised the technical feasibility of eradication.
The program has conducted surveillance at remote trace sites across the Northern Territory, with browsing ant only detected at Jabiru. Indigenous ranger groups have undertaken 32 surveillance events across the Northern Territory, with no browsing ant detected.
Odour detector dogs will visit the six infested premises in Darwin in May 2021 for the final post-treatment surveillance event. The NT response program is currently planning proof of freedom surveillance and modelling activities for the infested premises in Darwin.
Current situation in QLD
Browsing ant was first detected in QLD in April 2019 at a shipping container yard at the Port of Brisbane (Fisherman Island). Surveillance activities indicate the ant has not spread beyond the immediate area of the detection.
Businesses that use this part of the port facility have been engaged to support surveillance, treatment and tracing efforts.
Biosecurity Queensland completed treatment at the infested premises in March 2020. National Border Surveillance and Biosecurity Queensland staff are continuing validation surveillance across the Port from September 2020 to confirm the treatment has been successful.
Biosecurity Queensland’s odour detection dogs are supporting the surveillance effort and will provide confidence that effective treatment of the infestation has been achieved.
The QLD response plan is currently on track for eradication of browsing ant.
Current situation in WA
The first detection of browsing ant in WA was at Perth Airport in 2013. This was followed by a detection at commercial properties in the suburb of Belmont in 2014. Browsing ant has now been eradicated from Perth Airport and Belmont with area freedom declared in 2016 and 2017 respectively.
Further browsing ant infestations were found at Welshpool and Kewdale in Perth in 2017. These infestations may be linked to the original infestation at Perth Airport, possibly due to the movement of cargo between the airport and these areas. In 2018, two browsing ants were detected at an RAAF Airbase in Bullsbrook.
Following treatment at Welshpool, Kewdale and Bullsbrook, and multiple surveillance visits over two years with no browsing ant detections, clearance surveillance was undertaken at the three IPs in January 2020. A total of approximately 40 hectares across the three infested premises underwent clearance surveillance using odour detection dogs, with no detections of browsing ant.
Detections of browsing ant at new infested premises in January 2020 and April 2020 in Welshpool and in March 2020 in Bayswater did not trigger the response plan as they were linked to known infestations. These sites are undergoing treatment, surveillance and tracing activities.
Significant detections in Fremantle Port (December 2019) and East Rockingham (June 2020) triggered the response plan, as they could not be traced to a known infestation. The National Biosecurity Management Consultative Committee has considered these detections and agreed that browsing ant remains technically feasible to eradicate.
Browsing ant has not been detected in regional areas of WA to date, with further regional surveillance underway.
A National Biosecurity Management Consultative Committee meeting was held in September 2020. At this meeting, the committee agreed in-principle to support a revised response plan to extend the program’s duration by six months to June 2022 and to re-phase the budget and milestones accordingly.
About browsing ants
Browsing ant is a slender ant and is a consistent shiny dark brown colour. It is 3–4mm in length with long antennae and long legs and runs about in a haphazard manner when disturbed.
It occupies a range of habitats, including the ground, leaf litter, trees and infrastructure such as electrical boxes.
The immediate impacts of browsing ant are considered to be environmental. It forms super colonies and can kill and displace native ants and other insects. It farms and protect scale insects which can eventually kill the plants it lives, indicating its potential for impacts to agriculture and horticulture. It is not harmful to people or pets.
Browsing ant is commonly found in the Mediterranean, Southern Europe, Western Asia and North Africa.
What you need to do
It is important that people who live or work around the affected areas in the NT, QLD and WA are vigilant for this ant and report any suspect sightings.
Ants can hitchhike on goods and vehicles. In particular, they can be moved with shipping containers and cargo, as well as in soil, mulch, fertiliser and plant material.
Before leaving any site where ants are present, check that they aren't in your consignment, and haven't crawled onto vehicles, equipment or clothing. The movement restrictions mandated at infested sites must be adhered to, so this ant is not inadvertently moved out of the area or interstate.
If you think you've found a browsing ant population, you must report it to the Exotic Plant Pest Hotline on 1800 084 881 as soon as possible.