Monday, 8 July 2013

Caterpillar Nursery

Last Thursday (July 4th), my Dad came back from a 'wildlife walk' clutching his hat as if he was never going to let it go. He opened up the hat to reveal about 20 (probably more!) Peacock butterfly (Inachis io) caterpillars! Great news for me, but not so much for Dad as his hat was covered in caterpillar frass (fancy word for poop)!
Peacock caterpillars aren't particularly spectacular, being black in colour and slightly spiky. My Dad informed me that in the place he had found them (along the River Humber, near Hessle) there had been hundreds of them feasting upon Stinging Nettles, their food plant.
We decided to rear them, and moved the caterpillars into an old 'Exo Terra' (a supplier of many different terrariums) tank, which had once housed a stick insect, and already had a layer of soil on the bottom, aswell as some wood for decoration.
We added some Stinging Nettles, and released the caterpillars into their new home! I have to admit, I have never seen caterpillars quite as active as this species before now!

 Here's a picture of our caterpillar nursery! If you look carefully, you can see several of the inhabitants crawling about and munching away.

If you looked carefully at the previous picture, you may have noticed several pupae (chrysalises) hanging from the lid. Last night (July 7th), I noticed a few caterpillars hanging upside down by their back ends. One of them had already turned into a bright green pupa! It surprised me by wriggling, then going still.
The next day, we discovered that there were more pupae, and that after a while, they turned dark green. There are currently 12 pupae in the caterpillar nursery, but I suspect that there will be more by tomorrow!

A close up of a freshly emerged pupa (bright green), surrounded by older ones (dark green and brown).

This pupal stage should last between 3 to 4 weeks, though longer periods (sometimes all through the winter) have been recorded. Keep an eye out for another post about emerging adults!
The rearing of the caterpillars is part of my studies into metamorphosis, see my previous post, A Tank For Tadpoles.

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