Is it a twig? Or a Carausius morosus?

It looked as though the south-easter wind had blown a twig against the dark green vibrecrete boundary wall. It was just stuck there, completely motionless.

A twig stuck on the wall?

“I think it’s just a twig, but go on, touch it,” hubby said, daring me.

“Yeek! It moved!!”

It moved!

What I had taken as a partly split top tip of a twig (try saying that quickly! ;-)), revealed itself to be two waving antenna or feelers, and a pair of front legs, attached to a body with a segmented tail and two more pairs of legs.

A peculiar insect

A stick insect!

With surprising alacrity, it strode along and down the wall, clearly looking for a more camouflaged shelter. Hubby bravely held out his hand, inviting it to climb up, which it did!

D’you need a lift?

Then he carried it briskly into the back garden, where we found a safe spot for it in the hollow of the rhus tree, where a pile of leaves had accumulated. Much to our delighted amazement, it began to munch its way through the dry, crackling leaves.

A hungry stick insect in a leafy paradise

Curious, I later browsed the internet until I found out more about this peculiar group of insects known as the Phasmida (stick and leaf insects):

“In the daytime these typically long, slender stick-like insects remain remarkably well camouflaged in their habitat, commonly in woodlands, jungle or gardens. In fact, they may be present in gardens for years without being noticed. [No kidding! I think I’ve only seen one two or three times!]

Go out at night with a torchlight and they are then active, walking about and feeding. Many are not the boring, placid twigs people imagine them to be. Some species have an amazing range of behaviour, including using spiny legs in defence, as well as chemical defences. They are prepared to shed a leg in an effort to escape (capable of re-growing later if the insects are pre-adults).” (Biodiversy Explorer website)

The cheerful fella we encountered is a Carausius morosus (Laboratory or Indian Stick-insect). According to the description, their colour is

“various shades of dull green or brown, sometimes with darker mottling. In adult females the inside base of the forelegs are bright red. The thorax has a number of small tubercles (knobs). The thinner, shorter males are brown. It is believed that those reared in captivity are genetic females with male characteristics, but sterile, which are more frequent when these insects are kept at unusually high temperatures.” (Biodiversity Explorer website)

A closer look at ours revealed it to be an adult female! Look – you can see that the inside base of the front legs is bright red!

Look! You can see the red forelegs!

Isn’t that brilliant?

These odd creatures are parthogenetic, which means that the females lay unfertilised eggs, which hatch into females, which also lay unfertilised eggs, and so on. How weird is that?

“Females drop their eggs to the ground. The eggs are round, brown with a yellow knob, which hatch into fragile-looking brown nymphs after about 4-6 months. These moult six times, taking about 4-7 months to mature; adults live 4-6 months, laying several hundred eggs.

When disturbed, nymphs and adults may sway from side to side and may emit a fluid from the mouthparts. They may, however, simply drop to the ground. After all, this is the classic twig mimic, which can remain motionless for hours on end. It has been in culture in Europe since the late 1800s.” (Biodiversity Explorer website)

This particular species is a native of India, but they have also been introduced into the UK, Europe and the USA, and are also common in the area of Cape Town, South Africa.

So there you have it. The next time you see a twig, study it closely: it might just be a Carausius morosus. And do tell me if you see one!

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