A newly discovered stick insect measuring 40 centimetres and weighing slightly less than a golf ball may be the heaviest insect in Australia, scientists have said. The species, named Acrophylla alta, was found in the high-altitude forests of the Atherton Tablelands in north Queensland.
Researchers believe its large size may be an adaptation to the cool, wet environment where it lives. The discovery was documented in a peer-reviewed study published in the journal Zootaxa, which noted the insect likely outweighs the giant burrowing cockroach, currently considered Australia's heaviest insect.
James Cook University researcher Professor Angus Emmott said a social media post helped lead to the discovery. His co-author, Ross Coupland, was sent a photo of a stick insect and suspected it might be a new species. After several nights of searching, the pair found a large female between Millaa Millaa and Mount Hypipamee, high in the canopy, requiring a long stick to bring it down.
Emmott said the species had likely gone unnoticed because its habitat is difficult to access. “It lives high in the canopy. So, unless you get a cyclone or a bird bringing one down, very few people get to see them,” he said. The next challenge is finding a male, which is proving difficult due to their slender size and distinct appearance from females.
Queensland Museum entomologist Nicole Gunter said the discovery fills a gap in knowledge about Australia's biodiversity and highlights how much remains unknown. She estimated up to 70% of Australian insect species are currently undescribed. “Recognising this species as distinct is also important for its conservation. We can’t conserve a species if we don’t know it exists or where it occurs,” she said.
