Stick At It!

Insects are the largest and most diverse genre of living creatures on this planet – and when it comes to their look, they certainly like to mix it up a little – this is certainly true of the rather strange group known as the Stick Insects.

So called due to their resemblance to a, well, stick (or sometimes a leaf) these critters also go by the names of stick bugs (or bug sticks), stick animals, walking sticks or even ghost insects!  To give them their correct title, they belong to the order of Phasmatodea (which derives from the Greek for phantom, hence the name ghost, which refers to their ability to blend into their surroundings).

Why have they gone to all the trouble to evolve into such strange shapes?  The most obvious reason is for camouflage, which affords them protection from predators – now you see me… now you don’t!

As well as being able to blend in with, or mimic, their surroundings, stick insects also have other lines of defence to call upon against those unwanted visitors – the ability to produce a toxic secretion which gives off an unpleasant odour; lines of spines on their legs and what’s known as a startle display, which results in giving those bothering them an unwelcome surprise by flashing hidden colours and patterns to put off the would-be diners.

If all these efforts fail, they can also “play dead” which can help to deter any creature looking for a fresher meal and if the worse comes to the worst and a hunter gets them by the leg, then no problem, because stick insects have the ability to lose a leg and regenerate one – how handy (or is that leggy?)!

All these defences aren’t surprising, as there are plenty of predators lining up to munch on these guys, including birds, other insects, spiders, rodents – and even bats, who especially view them as a delicacy.

Being herbivores themselves, stick insects munch on the very surroundings with which they blend (hopefully they don’t accidentally take a bite out of themselves by mistake!!) – especially as they prefer the cover of darkness and have a nocturnal habit.

Stick insects are well dispersed throughout the world, favouring tropical zones and sensibly avoiding the artic regions.  They are a popular choice as an exotic pet and have been a favourite companion from the time of the Chinese Han dynasty, when they were believed to bring good luck.

You might not think them too dynamic, but a closer look reveals these guys are most definitely into rock ‘n’ roll – they like to sway gently back and forth as they move along – it’s thought to resemble the movement of vegetation in the breeze.

When stick insects get together, they’d better get along well with their chosen partner, because they have one of the longest pairings in the insect world – it can last for days or even weeks, with one tryst being observed for over 10 weeks!  It’s thought it’s an effective way for the males to guard the females and ensure that it is them alone that will father her young; but the females do win too, because they are afforded greater protection when coupled to the male, so maybe it’s a sneaky way to enhance their survival rate! 

On the subject of reproduction, one of the most unusual things about stick insects is that they are able to reproduce without the need for males (sorry boys!) – yes amazingly, female stick insects can produce mature female eggs that grow into female adults without the need for a male!  If they do mate in the more usual way, then the brood produces male adults also.  Indeed, there is one species of stick insects from which a male has never been found! – female domination!

When laying her eggs, the female stick insect spreads them around as she goes, choosing such places as the undersides of leaves – often the eggs resemble seeds, the hope being that egg hunters wouldn’t give them a second look!  One species of stick insects have a symbiotic relationship with ants, who kindly give the stick insect eggs a home in their nest until they hatch, in return the ants get a meal from the material surrounding the outside of the egg (which doesn’t harm the egg inside).

Once hatched, the nymphs grow to adulthood via a series of moults, eating their old skin to help avoid drawing attention to themselves – waste not, want not I guess!

One claim to fame for stick insects is that they proudly hold the title for being the longest insect found in the world to date.  The record holder (catchily named Phobaeticus Chani!) measured an incredible 62.4cm (24 ½ inches) long!

Another claim to fame is that stick insects have even inspired robotics engineers, who have studied the way in which they move around and applied this motion into their robotic creations!

Yep there’s definitely more to these guys than you can shake a stick at!!