Australia’s heaviest insect ever discovered in Queensland after eluding scientists for years

Scientists in northern Australia have discovered a new species of stick insect so large and elusive, it evaded researchers until now, despite living in plain sight, high in the rainforest canopy.

The insect, named Acrophylla alta, was identified by researchers from James Cook University after being spotted in the high-altitude rainforest of the Atherton Tablelands in Queensland. Measuring 40 centimeters (16 inches) long and weighing 44 grams (1.55 ounces), about as heavy as a golf ball, it is now considered the heaviest insect ever recorded in Australia.

Hidden in the canopy for centuries

The discovery began with a photo sent to Emmott and fellow researcher Ross Coupland. The pair trekked to the remote rainforest to investigate, eventually locating two female insects perched high among the trees near Millaa Millaa. They had to carefully dislodge the insects using a long branch.

The insects were then studied in captivity, and when one laid eggs, researchers compared them to known species. Each stick insect species has uniquely shaped and textured eggs in this case, the eggs revealed they were dealing with a species unknown to science.

Evolution in isolation

Scientists believe the insect’s massive size is an evolutionary response to its unique habitat. The cool, moist environment of the high-altitude Wet Tropics likely led to the development of larger, heavier bodies that help the insects regulate their temperature.

A reminder of the unknown

Two specimens of Acrophylla alta are now housed at the Queensland Museum for further study, but researchers are still searching for a male, typically smaller and morphologically different, to complete the classification.