Thorny devil walking stick

The wingless thorny devil walking stick belongs to the family of stick insects (Phasmatodea) and often exhibits a change in body colouration as it develops. Whilst juvenile individuals are greenish in colour, adult specimens can take on various shades ranging from brown to greenish or greyish hues. The body of this species is flattened and characterised by small spines arranged along its sides.

There is marked sexual dimorphism in body size and specific morphological characteristics. Females reach a body length of around 10 to 12 centimetres, whilst males tend to remain slightly smaller. A key distinguishing feature between the sexes is the ovipositor, a pointed organ on the abdomen of females that is used for laying eggs.

Distinguishing the thorny devil walking stick from the spiny ghost grasshopper (Eurycantha calcarata) is difficult due to their external similarity, but it is possible on the basis of certain characteristics. Compared with the spiny ghost grasshopper, the male thorny devil walking stick has even more pronounced spines. Furthermore, the wingless thorny devil walking stick is, on average, slightly smaller than the spiny ghost grasshopper. It also has a more pronounced, generally rougher body structure, whilst the spiny ghost grasshopper has a smoother surface.

The two species also differ in their behaviour: whilst the thorn ghost grasshopper prefers the ground or lower layers of vegetation as habitat, the wingless thorny devil walking stick is more frequently found in higher branches. Furthermore, the thorny devil walking stick reacts much more sensitively to external stimuli or threats than the rather shy spiny ghost grasshopper.

These differences in morphology and behaviour are important for species identification and enable a more precise taxonomic classification within the order of phantom grasshoppers.