We need to talk about the impact the bushfires are having on insects

By Angela Heathcote January 21, 2020
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Koalas are cute and cuddly, but life on Earth depends on insects.

David Yeates, the Director of the Australian National Insect Collection, is used to insects getting the short-end of the stick. “Insects are small, whereas koalas are cute and everyone loves things that look cute,” he says. 

Indeed, stories of the impact the recent bushfires have had on Australian wildlife have centred around the adorable marsupials. Images of burnt paws and singed fur are, naturally, both heartbreaking and evocative. 

But according to David, we should be more concerned about what impacts the unprecedented fires are having on Australia’s insect populations – a group of animals that could make or break the Australian environment. 

It’s estimated that over one billion animals have been killed or injured during the bushfires, including at least 20 threatened species that are now closer than ever to extinction. But entomologists such as David will struggle to fully estimate the impact of the fires on insects.

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Concerns about an ‘insectageddon’ have featured in headlines over the past year – most stories concerning insect populations of the Northern Hemisphere, rather than Australian populations. “We don’t have the data for insect declines in Australia,” says David. “Scientists in the Northern Hemisphere have done more surveys over several decades.”

Following a symposium in Brisbane late last year, a large gathering of entomologist, including David, found they only had conclusive data for declines in three Australian species – the bogong moth, Key’s matchstick grasshopper and green carpenter bee. There’s undoubtedly more, but a lack of funding and long-term data means definitive conclusions are hard to delineate.

David’s thorough knowledge of Australian insects gathered over the past 30 years, however, leads him to believe that the recent bushfires may have caused irreversible damage to Australia’s insect populations, due to the intensity and extensiveness of the fires, which he says will make recovery difficult.

“Typically, when a fire goes through a patch of bushland it’ll burn some areas quite heavily but will leave other areas mostly untouched,” David says. “Insect populations survive by having a few insects populate those untouched areas, but there won’t be many of those untouched pockets.”

Out of the 250,000 known insect species that exist in Australia, David says many are unnamed and have narrow distributions. “Of some species, we may only collect them twice in our whole lifetime,” he says. “We’re now worried that some of those uncommon, narrowly distributed little beetles and other insects may have gone extinct through these fires. They just couldn’t escape.”

David’s second-biggest concern is the damage the bushfires have wreaked on Australia’s UNESCO World heritage-listed Gondwana rainforests and its ancient insect inhabitants. Analysis by The Guardian has reported that 80 per cent of the Blue Mountains and 50 per cent of Gondwana rainforests have burned. 

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“The rainforests have old, evolutionary roots from the mesozoic era, when the dinosaurs were around,” David says. “Australia was a much wetter and cooler place, and our rainforests are not adapted to fire at all. They can’t regenerate after being burnt. 

“There are a lot of mesozoic insects that live in those rainforests that are evolutionarily fascinating and are our amazing biological legacy. 

“Think strange primitive moths and sucking bugs, unusual beetles and strange flies that only live in those rainforest environments. These ancient species have given rise to the animal lineages that are common in our more open forests. They are the remnants of ancient life.

“Their habitat has disappeared.” 

Beyond the immediate impacts of the fires, a lack of insect life is also fuelling the starvation events being experienced by birds and mammals. “Around 60-70 per cent of birds are insectivores. Even if you had all the birds back in the forests, they’d starve without insects. 

“The insect survivors will emerge from what’s left of the landscape, but they’ll also starve because there’s nothing for them in the way of plants or anything they would typically feed on. I’ve advocated for some wildlife carers to think about distributing native flowering plants to different fire grounds where appropriate to help in the immediate aftermath.”

Other measures may include harnessing the many dead animal carcasses and, rather than burying them, leaving them out for insects to feed on. Entomologists like David, however, will be focusing on gathering more robust data on Australian insect populations and how potential declines may change the Australian landscape.

“Koalas are lovely… Australia’s ecosystem wouldn’t collapse without them though. If we lost insects, ecosystems would collapse. They’re so heavily involved in nutrient recycling and pollinating, we can’t live without them.”