As a notifiable pest, the browsing ant is a potential invasive species that Australian pest managers should be able to identify.
The browsing ant (Lepisiota frauenfeldi), native to the Mediterranean area and northern Africa, has the potential to be a serious invasive pest. In Australia there have been a number of incursions since 2013 in WA, QLD and the NT. All known incursions in WA and QLD have been treated and are in a surveillance phase, with one active infestation in the NT that is expected to be resolved by the end of 2025.
The red imported fire ant may be getting all the headlines, but the browsing ant also represents a significant threat to the environment and agriculture in Australia, so pest managers should know how to identify this important ant.
The browsing ant is a small dark brown ant, with a body 3-4 mm long, but with long legs and antennae, not dissimilar to crazy ants. Like crazy ants, they run around in a haphazard manner when disturbed. However, unlike crazy ants that bite and inject formic acid, browsing ants do not sting when disturbed. They are sometimes also confused with Argentine ants based on size and colour, but the long legs and antennae together with haphazard movement distinguish the browsing ant from the Argentine ant.


They make loose nests on the surface of the ground or under objects such a timber mulch and rubble – again, very similar to Argentine ants. However, they will happily nest inside buildings often targeting electrical boxes. They form multi-queen, multi-nest supercolonies that can expand by budding – classic characteristics that are common to many invasive ants. They are also omnivores, eating other invertebrates, but also tending sap-sucking insects for honeydew.
In Australia, the browsing ant was first detected at Perth airport in April 2013. In June 2015, it was detected at the Port of Darwin in the Northern Territory, and in April 2019 at the Port of Brisbane in Queensland. Since 2013, authorities have detected ten infestations in WA, 23 detections in QLD and one in the NT. With a large number of infestations detected across the country, it was important to try and determine whether these infestations were from one or more incursions.
Researchers in WA used whole mitochondrial genome analysis to determine the source of these infestations.1 They determined that each state had their own separate incursion and that the infestations in WA were probably a result of two separate incursions. While it is not known where or how the ants arrived, the nearest countries known to have browsing ants are Timor Leste off the north coast of Australia and Malaysia.
The global knowledge of browsing ant biology, behaviour and control options is somewhat limited. Government control programs in Australia use hot dog pieces and sniffer dogs for monitoring. Government control programs have used specially formulated granular ant baits and sprays to gain control.
As they don’t sting like red imported fire ants, they don’t represent a health threat. However, they do represent an ecological and agricultural threat. Like many invasive ants, if they become established, they will outcompete local ant species and upset the local ecosystems, with unknown impacts on other animals and plants. With their known preference for feeding on honeydew, their protection of sap-sucking insects, which in turn promotes sooty mould growth, can impact agricultural and horticultural plants.
Although there have been some incursions and the browsing ant could easily spread to many parts of Australia and impact the environment, it isn’t actually a reportable pest in all states and territories (for example it is in the Northern Territory but isn’t in Queensland). Nevertheless, if a pest manager does suspect potential browsing ant activity, it should be reported to the relevant state authority.
1 Prodhhan, M.A et al. (2024). Whole mitochondrial genomes reveal the relatedness of the browsing ant incursions in Australia. Scientific Reports 13, 10273 (2023). https://doi.org/10.1038/s41598-023-37425-1