La Nina's wet conditions trigger possible Aussie insect 'explosion'

CHOMP, CHOMP, CHOMP: Wet and humid conditions from La Nina are ideal for insects like locusts and mosquitoes to boom.

CHOMP, CHOMP, CHOMP: Wet and humid conditions from La Nina are ideal for insects like locusts and mosquitoes to boom.

First came the fires, then a pandemic, floods and now a plague of locusts could swarm parts of eastern Australia.

Months of rain along with bouts of hot weather brought on by the La Nina climate system has created an environment primed for insect breeding.

La Nina summers are typically wetter than average, with the increased rainfall leading to a surge in mosquito and fly populations.

Australian National University insect physiologist Paul Cooper said there was "good potential" that a locust plague could hit Queensland and spread south to NSW and Victoria.

"We might be looking for that in January and February," he said. "Although the eggs would be developing with all the rain, the question is - has the rain destroyed so many plants that there's nothing for them to feed on?"

Locust plagues begin when large inland areas receive sudden heavy rainfall, which stimulates more grass growth for the insects to eat and leads to more eggs.

The Australian Plague Locust Commission's December update said there could be an increase to overall population levels over summer with "swarm formation" likely in NSW's Riverina district leading to possible region-wide infestations.

However, University of Melbourne biologist Ary Hoffmann said it was too early to tell whether any plagues will occur.

"There's one species showing moderate numbers. It may be the case we get a plague, we may not, they are boom and bust insects," Professor Hoffmann said.

In general, both experts agree we are likely to see lots more insects this summer, thanks to La Nina.

"After a spring like we've had, you get a lot of plant growth, and so there's a potential for insects that eat plants to explode," he said.

Associate Professor Cooper pointed to mosquitoes, flies, earwigs and slaters in particular.

"What you're seeing is probably a much greater survivorship of the eggs simply because there's so much water around on the ground," he said.

He said flies and mosquitoes were attracted to human smell, the carbon dioxide we emit and the water in our eyes.

"Your teardrops are actually quite attractive to flies," Prof Cooper said.

Prof Hoffmann said that although insects got a bad wrap, they had a vital role in supporting the ecosystem.

"Without insects we couldn't do many of the things we do. Even mosquitoes are important fish food," he said.

Australian Associated Press