Wednesday, 8 July 2020
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Rain, warm weather perfect for fire ants

The substantial falls of rain in the Fassifern is good news for landowners trying to get rid of fire ants from their backyards, paddocks and agricultural land.

The National Red Imported Fire Ant Eradication Program Science Leader Dr Ross Wylie said the wet weather meant the community may see fire ant nests much more clearly, as the ants build their nests higher in the wet.

“This is because this ‘super pest’ thrives in these sorts of conditions, especially when combined with the high levels of humidity we’ve been experiencing,” said Dr Wylie.

“We urge the community to check their land now for fire ants and report any sightings to the program.

“We particularly need to hear from landowners in the western part of the South East Queensland fire ant infestation in the Lockyer Valley and surrounding areas where we’ve spent over two years treating the ‘super pest’.”

Fire ant treatment schedules can also be affected by weather, and the program recommends that people don’t self-manage immediately before or after wet weather events.

“One of the main reasons that fire ants are such a problem is that some of them have the ability to fly and can quickly establish new colonies some distance away from the mother colony.

“When the conditions are right, like they are now, hundreds of fire ant young queens take to the air to mate — flying between two and five kilometres.

“They can reach an altitude of up to 300 metres, although most have been detected between 60 to 150 metres.”

While many of the queens become prey to insects like dragonflies and birds, a significant number survive to form new colonies.

“The flights can occur anytime, but are more likely to occur in the warmer months of summer during periods of high humidity following rainfall, after weeks of dry weather.

“Previously in Brisbane, synchronised flights have been observed in January and February after heavy rain.”

Dr Wylie said the program used the research done into the flight range and behaviour of young fire ant queens to help plan the program’s eradication strategy.

“Fire ants are also known to spread during flood-like conditions — a survival technique which evolved on the flood plains of major South American river systems,” he said.

“They have the ability to survive flood waters by linking their bodies together to form rafts.

“The queen and the larvae are loaded on top of the raft with food and as the flood waters rise they float away.

“They can float for weeks until they come to dry land or a place where they can start a nest again.

“This rafting is another way by which fire ants can colonise new areas or higher ground and this behaviour has been observed in South East Queensland, including in Purga near Ipswich.”

Dr Wylie said after wet weather events the program expects increased fire ant reports.

“Recent changes to the treatment have ensured the program can more quickly meet these increases,” he said. 

“Alternatively, people can opt to self-manage — engaging a pest manager or purchasing fire ant bait from a local retailer and treating their property themselves.”