Thursday, 28 June 2018

Caterpillar Diaries (Part 11)

The last one to pupate!
In the last two weeks, my caterpillars have been slowly building their cocoons. One by one, day after day, their numbers have been dwindling. The amount of food going in and the frass that I have to clear out has been less of a chore, but their slow, sluggish behaviour has been causing me some concern. Their not as hungry as they once were and prefer climbing and wandering around the box and everything within it. Sadly, 3 of the 25 caterpillars have died, perhaps being unable to locate the limited amount of leaves I put in there, which is getting harder and harder to keep fresh every day. Now, only one remains and I'm glad to say that it has decided to join the others by pupating as well.

Building the foundation
As it is the last one, I've been watching it start building its cocoon. It was originally building it on the paper towel and a leaf instead of the egg cartons. So I've carefully removed the leaf and reduced the size of the towel and placed it inside one of the cartons where its more convenient for me. Once it starts producing silk, it won't stop until it is fully covered, repairing any damage I've made from moving it without any problem. The silk is pretty strong and slightly tricky to pull things off that's attached to it and it hardens very quickly. The caterpillar first lays down the foundations, flexing its body to fix the strands of silk to one point to another that's behind it with the caterpillar remaining in the centre of it all.

Weaving silk into a messy 'spider's web'
As soon as the foundations are attached, it binds more and more of the silk over it, creating what's like a messy spider's web. It then simply weaves this 'web' with more silk, slowly plugging up the gaps until you can't see the caterpillar anymore. It's a long process and will take as much as half a day to complete, so I expect this individual will have finished by the time I wake up tomorrow. The silk will also react to the air and will change colour to brown by that point too.

Plugging up the gaps
Slowly vanishing behind a sheet of silk
By morning it will be complete
With no more caterpillars to look after, I am free from collecting food for them and cleaning up their poo. You just don't know how relieved I am about that. No longer will I have to keep moving them to empty the massive pile of frass they leave behind or get my hands scratched to bits by bramble thorns! I'm free!! But not quite. Now that they are cocoons, all I have to do is cut up the sections of egg box that they are on and store them into a smaller box. Then all I need to do is wait until they emerge next spring. There is a slim chance that they could emerge early in late August and early September, but hopefully that won't happen.

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