Homeowner shocked as backyard taken over by 'metropolis of ant mounds'

A resident in a NSW town south of Sydney was shocked to discover an 'ant city' had suddenly taken over her grass following recent rain.

A once beautifully manicured lawn has become a "metropolis of ant mounds", a perplexed homeowner has revealed, sharing a newly formed "ant city" has popped up in her backyard.

The woman says she can no longer use her yard thanks to mounds of soil covering the grassed area with potentially thousands of "small black ants" now calling her backyard home. Incredible photos show patches of brown dirt lining her footpath and spread across the grass at her home near Kiama, a coastal town south of Sydney.

The incredible sight is the workings of the funnel ant, entomologist Nigel Andrew confirmed to Yahoo News Australia — a native species that's "prolific" up and down the east coast of Australia. Each one of the moulds, or ant nests, can contain up to 100 individuals he said, and it's a pretty common sight after rain, of which there's been plenty in NSW lately.

"This happens usually after there's been a big rain event. Effectively, they're trying to dry out their nests and they do this to aerate the soil," he explained.

Ant mounds caused by funnel ants are pictured, left in a backyard near KIama. Right: The ant mounds are shown along the edge of a path.
The NSW woman was shocked to discover what she described as an 'ant city' in her backyard after noticing dozens of ant mounds following rain. Source: Facebook

Homeowner desperate to remove 'ant city'

Desperate to regain use of her backyard after the ants seemingly took over, the homeowner sought the help of fellow community members on Facebook.

"Our yard has become a metropolis of ant mounds. We probably should have come up with some eradication method before it got to this scale. Do we need a professional exterminator?" she asked calling her backyard an "ant city".

"They are small black ants and thank goodness not in the house but they need dealing with as the yard is horrible to use. Anyone else got a backyard burb of ants?"

Left: Funnel ant on green leaf. Right: Dirt mound caused by funnel ant.
Funnel ants are commonly found along the east coast of Australia and can cause significant damage to lawns and soil. Source: Australian Museum.

Ants can 'damage soil quite a lot,' expert warns

Andrew, a professor at Southern Cross University, said the native ants are known to "cause a lot of pain and angst for homeowners" and have the potential to "damage soil quite a lot". "If people walk on them or if you have machinery moving on them, it can cause the grass and the soil to collapse," he explained. It's a common sight in backyards and even golf courses.

Unfortunately for Aussies, the only way to fix the problem is by exterminating them. But even then they'll likely return, Andrew said.

"You won't actually get rid of them. If you do try and sort of spray them in this season, they're probably going to come back in a year or two anyway," he explained but said adding shrubs and other foliage to gardens can help.

That's because, the funnel ants thrive in open, bare grass, so introducing other plants "gives a bit more complexity to the environment". "The more structural diversity, or the more plants and shrubs that you have in a backyard, that attracts other insects," the entomologist explained. "These will compete with the ants, reducing the impact of the funnel ants in your garden".

Dirt mounds caused by funnel ants in a NSW backyard.
Each mound, or nest, can contain up to 100 ants. Source: Facebook

Funnel ants 'can be aggressive'

Thankfully, the Aussie woman likely doesn't need to worry about the ants entering her home as they often stay beneath the grass in their nests. But be warned, the little critters "do have a sting on them" like many ant species.

"They can be aggressive if you get close to their nest, for example, if you sit on them or are playing with them, but it's like a lot of ants," Andrew explained, but said they're "nothing like the fire ant". "So if you do have a sensitivity, they can be painful and you can put an ice block or something on the sting. That will reduce the swelling if you do get stung by them."

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