An Australian insect lays eggs fitted with a structure that scientists had never observed before.
The discovery comes from a major reassessment of stick insects in the genus Anchiale living in Australia. These large insects, camouflage experts, can be surprisingly difficult to distinguish. Their size and color sometimes vary greatly, to the point that individuals of the same species were long classified under different names.
Female Anchiale mabiensis photographed in its natural habitat.
Credit: Angus J. Emmott / Jones et al., Austral Entomology (2026), CC BY 4.0.
To clarify the picture, the researchers compared specimens preserved in museums with others collected in the wild. They studied their appearance, DNA and even their eggs. The result: Australia is home to five Anchiale species, including two that have just been described for the first time.
One of them, Anchiale mabiensis, holds the biggest surprise. Its eggs measure less than 3 mm and have a kind of small lid at one end. The young stick insect opens this part when it emerges from the egg.
Yet beneath this lid, the researchers discovered two to three internal rings. Nothing comparable had ever been described in stick insects, or even in their closest relatives. The other Australian Anchiale species studied do not have these rings.
Anchiale eggs, dorsal and lateral views.
What are they used for? For now, no one knows. They could play a role during development or hatching, but their function remains to be determined. Their shape already gives scientists a new way to recognize Anchiale mabiensis and compare it with other species.
Eggs are also very useful for identifying stick insects. Depending on the species, they may differ in shape, texture or color, or bear various small structures. In Anchiale mabiensis, they are brown, heavily sculpted and lack the small pale appendage found in several related species.
This new species also appears to have a very limited range. It is mainly known from the wet forests of the Atherton Tablelands in northeastern Australia. Another newly described species, Anchiale robusta, also lives in the tropical regions of Queensland and can reach about 16 cm in females.
The researchers now want to compare these Australian stick insects with those from New Guinea and neighboring islands. Their DNA could reveal how these large insects became distributed throughout the region and determine whether other species are still hidden among stick insects currently considered identical.