A large, winged stick insect blamed for stripping trees bare in periodic outbreaks across coastal Queensland has turned out to be five separate species, not the two long assumed by collectors and naturalists. Braxton Jones, a postdoctoral researcher at the University of Sydney, led a revision of the genus Anchiale that combined museum specimens, new field surveys and DNA from 32 individuals, and the results split what had been treated as a single widespread species into three previously unrecognized ones. Two of those five are entirely new to science; a third had been folded into a different species for more than a century and is only now being separated back out.
Jones described the process as detective work as much as fieldwork, since some of the clearest evidence for telling the species apart came not from the adult insects themselves but from their eggs. Female Anchiale can be identified reliably from wing colour, shape and length, Jones found, but the eggs carried a signature that held up even when the insects looked similar to the naked eye — a distinction that mattered because the genus is large-bodied, frequently photographed, and yet had never been through a full taxonomic review despite being among Australia’s most commonly reported stick insects.
The genus has a reputation beyond its size. Anchiale stick insects are known for forming plague-like population outbreaks that can strip the foliage from entire stands of trees, a behaviour naturalists had long attributed to a single widespread species moving through the landscape in waves. Splitting that species into five means those outbreak reports were never as uniform as they appeared — different regional populations, feeding on different host plants and confined to different ranges, were being lumped together under one name every time an outbreak made local news. Sci.News, reporting on the same Austral Entomology paper, noted that the genus as a whole now comprises 16 species across Australasia, with the Australian contingent alone accounting for the five Jones’s team just resolved.
Two new species, one confined to a single forest
The first newly described species, Anchiale mabiensis, is smaller and more slender than its relatives, with adult females reaching roughly 11.5 centimetres. It has so far been recorded only in the Mabi Forest on Queensland’s Atherton Tablelands, a rainforest type the Commonwealth lists as a threatened ecological community, and researchers say large parts of the original forest have already been cleared for agriculture. The second, Anchiale robusta, is considerably larger, with females reaching up to 16.2 centimetres and males displaying large, mottled wings; it ranges across coastal rainforest from Tully to north of Cooktown, a stretch of at least 450 kilometres, and feeds on a variety of plants including acacias. Both species were published in a paper in Austral Entomology alongside the genus-wide revision.
An egg with a lid unlike any other stick insect’s
The eggs of Anchiale mabiensis carry a feature Jones says has never been documented before in any stick insect, or in any related orthopteroid insect group: a series of two to three rings forming a distinct lid on the egg’s surface. Other Australian stick insect eggs in the genus are typically glued to a surface, buried, or wrapped in a silk-like coating, but nothing in the existing literature matches the ringed lid structure Jones and colleagues found. That single anatomical detail became one of the more reliable ways to confirm the new species held up under scrutiny, because egg structure tends to stay far more consistent within a species than superficial traits such as body colour, which can vary with diet, age or region.
A third species freed after a century of mistaken identity
Alongside the two new descriptions, Jones’s team resolved a long-standing case of mistaken identity involving a stick insect from central Queensland that had been classified as part of Anchiale briareus for more than a hundred years. Combining anatomical comparison with genetic evidence from the DNA samples, the researchers restored that population to its own species, Anchiale albopunctata, separate from both A. briareus and the newly named A. mabiensis and A. robusta. Jones told the Australian Broadcasting Corporation that even among some of the country’s most photographed and frequently reported insects, species can still escape formal scientific recognition — a gap the genus-wide revision was specifically designed to close.
Why naming five species instead of two matters for conservation
Terry Carmichael of the Wet Tropics Management Authority said the understanding of invertebrate species in the region lags well behind other groups of animals, and that researchers routinely tell him they lack enough basic taxonomic data to guide conservation decisions. Splitting one widespread species into five narrower ones changes that picture directly: a population once assumed to be common and broadly distributed because it fell under one name can turn out, once separated, to include a species recorded in only a single patch of threatened rainforest. That is the situation now facing Anchiale mabiensis, found nowhere outside the Mabi Forest, where ongoing clearing means the newly recognized species’ entire known range could shrink further before most naturalists learn its name.
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This article was produced with the assistance of AI and reviewed by Morning Overview editors prior to publication.
