Saturday, 8 September 2012

The Newborn Nymphs of the Interesting Insects

Hurray! Today, I became a Daddy!

                     Well, not really me. And not really a Daddy. But my stick insects have had babies. Well, not babies. Baby, really. Just the one. My stick insects have had a baby. Well, when I say ‘had a baby’ I mean that an egg has hatched. Without any help from me. I spent this afternoon cleaning out one of the tanks and collecting the eggs from the sand at the bottom, with a magnifying glass and tweezers. Lots of eggs. And putting them in a plastic box, with a very slightly damp cloth under them. They should, everything going well, hatch in about three months or so. 

Guess who bought a macro lens?

That’s the beauty of breeding these things – you just can’t be sure, you have to just wait. It’s more or less certain that they will hatch, but you don’t know when. And then, when I was tidying up, I spotted it. A tiny, perfectly formed baby stick insect. So, where there is one, more will follow. Just a matter of time. How long depends on when the eggs were laid and which I have collected and which I have missed. The eggs are tiny. Here is picture of one and below it the same picture with dimensions added. 

Stick Insect Egg

Dimensions added

Close-up of the egg plug

The eggs are very dark brown or grey, almost spherical, with a tiny beige plug at one end, through which the new nymph will emerge. The eggs are about three millimetres long and the nymphs are about one centimetre long, like a tiny thread with legs. They grow quickly, moulting their skins as they grow, and reach adulthood in around six months. 

This is one reason why they are such great pets for children. They breed readily and are fascinating to watch as they grow, and very easy to keep; they need fresh food and a light misting with warm water once or twice a week, and to be well ventilated to prevent mould, with about four times their length in height in the container to allow them enough room to hang down and moult, and will thrive at room temperature. 

How many can you spot?

A fish tank, turned on one end and with a mesh cover, is an excellent home but an old sweet jar with small holes in the lid will suffice; avoid artificial light (red or blue bulbs if you must) and keep them out of direct sunlight. The ‘common’ stick insect is the Indian stick insect, also called the laboratory stick insect, Carausius morosus, the culture stock originated at Tamil Nadu, India, the captive population are almost exclusively female (about one in ten thousand wild insects are male – a male is hardly ever seen in captivity), and they breed by parthenogenesis. 

The adults are between eight and ten centimetres in length and feed readily on privet, bramble or ivy (although a couple of escapees of mine – since recaptured – have dined royally on a Swiss Cheese plant). They will take other green leaves – lettuce and pyrocantha are favoured; rose, raspberry and hypericum will sometimes be eaten – but any form of brassica or carrot should be avoided. 

Close up of the head

Phasmids are nocturnal and it is sometimes disconcerting to look into a seemingly empty tank during the daytime only to be surprised by the same tank at night, when it has somehow been magically filled with insects. The camouflage of the stick insect is rightly renowned, for they are maddeningly difficult to spot even when you know they are there, and it makes cleaning out a tank or cage an interesting exercise in having your wits about you – I move any old foliage into another container for a couple of days, just in case I’ve missed any of the little rascals. 

They employ two main methods of disguise – one is to rest with their limbs extended, perfectly still, like the proverbial stick or twig; the other is to rock like a twig swaying in a breeze, looking for all the world like they’ve been at the sauce all afternoon. 

Close up of the feet

Strangely, for a creature so well camouflaged, they have very vivid red flashes on their forelegs that, considering the lack of males, cannot be for attracting mates, so must serve a deterrent or warning purpose. 

Flashing the red flashes ...

I have not read anywhere how the stick insect tastes, (Frank Buckland, where are you now?), but bright colours in nature tend to point to a foul taste, although considering their penchant for deception, the stick insect may simply be pretending to be poisonous – I wouldn’t put it past them!

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