Invasive ants

Invasive ants have wheels, will travel!

The African black sugar antwas detected by the DPIRD in Maddington.

f AFRICAN black sugar ant with pupae.

f AFRICAN black sugar ant are voracious eaters, with an appetite not only for insects and small vertebrates, but also plastic.

Another invasive ant incursion in Perth has highlighted the risk of pests entering and travelling through Western Australia along the imported freight and cargo transport pathway.

The African black sugar ant (Lepisiota incisa) was detected by the Department of Primary Industries and Regional Development (DPIRD) in the suburb of Maddington, during national eradication program surveillance for browsing ant (BA) and red imported fire ant (RIFA). This was the first time the African black sugar ant had been detected in Australia.

It has since been detected at another six locations in the Perth suburbs of Welshpool, North Fremantle, Wattleup and Forrestfield. Almost all locations are commercial premises associated with the transport or storage of freight containers, imported goods, and materials in which ants can be easily moved, such as green waste. DPIRD technical manager John van Schagen said a nationally funded eradication program was underway. This has involved treatment of the infested sites and on-going posttreatment surveillance to monitor the effectiveness. “The African black sugar ant is a nationally significant pest, due to its potential impacts on the environment, economy, and social wellbeing,” Mr van Schagen said. “It is not harmful to people or pets, but poses a threat to native species because they are known to nest in undisturbed bushland and are aggressive towards other ants, and have a voracious appetite for insects and small animals.

PHOTO © DPIRD

Targeting the freight pathway

“They can also nest happily on commercial premises, and can build super colonies with the potential to stretch for hundreds of kilometres.” With DPIRD now running three national invasive ant eradication programs, all with possible entry pathways involving imported freight, surveillance is targeting the transportation network. This includes sea and air ports, and transport hubs for freight containers and cargo. Mr van Schagen said DPIRD had a proven good track record for invasive ant eradications. “In this instance, the likelihood of eradicating the African black sugar ant is good, as it is closely related to the browsing ant, which has been successfully eradicated from several locations in the past.”

Mr van Schagen said movement of imported freight and cargo was considered to be a common pathway for invasive ants. “Pests such as ants can spread when an infested freight container or cargo is moved from entry points such as ports to other locations, and when ‘carriers’ stored at the same location become infested and are then moved on. “Ant carriers could be other containers, vehicles and equipment, or materials that allow for easy transport, such as refuse, soil, green waste and building materials.” Mr van Schagen said the The likelihood of eradicating the African black sugar ant is good. commercial activities being carried out on the properties where African black sugar ant was detected supported the assumption of a freight transport pathway. “It is for this reason that surveillance is being carried out at locations where freight is likely to stop during its journey to the end user. “This includes freight yards, transport depots and warehouses, and freight end points such as industrial areas, mining sites and businesses in regular receipt of imported goods. “We are also visiting locations where carrier materials might be stored, such as waste recycling centers, earthmoving equipment hire companies, and nurseries.”

These locations are also being surveyed for evidence of BA and RIFA, and African black sugar ant is being looked for at surveillance areas specific to the BA and RIFA eradication programs. “In fact, the concurrent eradication programs are working in each other’s favour,” Mr van Schagen said. “By looking for all three ant species on properties being targeted by all three programs, we have been able to increase the intended surveillance areas for each species. “This increases the probability of detection, and therefore the likelihood of preventing spread and achieving eradication.”

The role of industry

Mr van Schagen said WA’s invasive ant eradication programs included the need to increase public and industry awareness, and the reporting of suspect ants. In particular, growers should be aware of the need to be looking for pests not just in their crops, but also in items on which pests can hitchhike. “While some invasive ants do not have a huge impact on primary industry production, we still need growers to be aware of their potential environmental, economic and social impacts, and the need to report suspicious ants. “The farm is a common end point for freight containers, imported vehicles and equipment, and imported goods, and so it would not be unusual for invasive ants to be present.” With the warmer weather approaching, DPIRD is urging everyone to start paying attention to ant activity, and to make reports to the department, even if unsure. “In Perth, we are seeking the assistance of industry and the public close to premises where invasive ants have been found, including Forrestfield, Welshpool, North Fremantle, Wattleup and Maddington.”

f INVASIVE ant detections at ports and container storage locations highlight the need for greater pest awareness and surveillance along the freight transport pathway (pictured here is the site of WA’s red imported fire ant detection in 2019).

“More than 50 agricultural and horticultural crops, as well as turf and nursery species, can be affected by invasive ants.

About African black sugar ant

• Shiny dark brown. • 2–3mm in length. • Thick blackish bristles. • Upper surface of the lower midsection has a deep notch on both ends. • Pronounced spine between the thorax and abdomen. • Hairless legs that are mostly yellow. • Features visible under a hand lens or microscope. • Establish interconnected nests with collaborative egg-laying queens. • Can potentially outcompete and displace important native ants. • Can disrupt whole ecosystems • Known to harvest plastic and infest electrical boxes and components, causing damage to infrastructure.

“They can damage and kill plants by tunnelling through roots and stems, and some ants will protect plant pests such as scale insects and Exotic ants can have a devastating impact on ecosystems. aphids, in order to feed on the 'honeydew' that results from plant damage.” Ants such as RIFA are also a threat to human and animal health, due to their ‘fiery’ sting. They have been known to attack young animals, stinging around the eyes, mouth and nose, and preventing animals from reaching food or water without being seriously stung.

MORE INFORMATION

More information is available from

agric.wa.gov.au/African-black-sugar-ant

and agric.wa.gov.au/ants

What are so bad about invasive ants?

Mr van Schagen said invasive ants were amongst the most serious global invasive pests, and were Australia’s seventh most important National Priority Plant Pest. Other invasive ants posing a threat to WA include red imported fire ant, browsing ant, yellow crazy ant, electric ant and tropical fire ant. “While native ants play an important role in maintaining healthy ecosystems, exotic ants can have a devastating impact on these ecosystems,” he said. “Similar to the African black sugar ant, they can build huge super colonies, are aggressive, feed voraciously and can damage electrical infrastructure such as irrigation and electrical wiring. Communities can also affected by invasive ants by making outdoor areas un-usable.”

Mr van Schagen said some invasive ants could also impact agriculture.

Report your observations!

MyPestGuide™ Reporter via online or app mypestguide.agric.wa.gov.au

Pest and Disease Information Service (08) 9368 3080 padis@dpird.wa.gov.au

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