Insect Population Decline Leaves Australian Scientists Scratching for Solutions

February 25, 2018

A global crash in insect populations has found its way to Australia, with entomologists across the country reporting lower than average numbers of wild insects.

University of Sydney entomologist Dr Cameron Webb said researchers around the world widely acknowledge that insect populations are in decline, but are at a loss to determine the cause.

“On one hand it might be the widespread use of insecticides, on the other hand it might be urbanisation and the fact that we’re eliminating some of the plants where it’s really critical that these insects complete their development,” Dr Webb said.

“Add in to the mix climate change and sea level rise and it’s incredibly difficult to predict exactly what it is.”

‘It’s left me dumbfounded’

Entomologist and owner of the Australian Insect Farm, near Innisfail in far north Queensland, Jack Hasenpusch is usually able to collect swarms of wild insects at this time of year.

“I’ve been wondering for the last few years why some of the insects have been dropping off and put it down to lack of rainfall,” Mr Hasenpusch said.

“This year has really taken the cake with the lack of insects, it’s left me dumbfounded, I can’t figure out what’s going on.”

Mr Hasenpusch said entomologists he had spoken to from Sydney, Brisbane, Perth and even as far away as New Caledonia and Italy all had similar stories.

The Australian Butterfly Sanctuary in Kuranda, west of Cairns, has had difficulty breeding the far north’s iconic Ulysses butterfly for more than two years.

“We’ve had [the problem] checked by scientists, the University of Queensland was involved, Biosecurity Queensland was involved but so far we haven’t found anything unusual in the bodies [of caterpillars] that didn’t survive,” said breeding laboratory supervisor Tina Kupke.

“We’ve had some short successes but always failed in the second generation.”

Ms Lupke said the problem was not confined to far north Queensland, or even Australia.

“Some of our pupae go overseas from some of our breeders here and they’ve all had the same problem,” she said.

“And the Melbourne Zoo has been trying for quite a while with the same problems.”

Limited lifecycle prefaces population plummet

Dr Webb, who primarily researches mosquitoes, said numbers were also in decline across New South Wales this year, which was indicative of the situation in other insect populations.

“We’ve had a really strange summer; it’s been very dry, sometimes it’s been brutally hot but sometimes it’s been cooler than average,” he said.

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