Instars and moultings

Traces of the silkworm moulting between the 1st and 2nd instar;

Silkworms, in the larval stage, go through an enormous size increase and, periodically, they need to shed their skin in order to be able to grow - they are born with just a few millimeters and they grow to be 7 or 8cm long before cocooning.
They go through 5 instars and they shed their skin in between them. So, they shed their skin four times during larval stage. The first molt occurs about a week after hatching. Since the silkworms aren’t “living” with me (they are happily installed in Serralves), otherwise I would be obsessively watching over them, in this initial stage I didn’t see any of them go through the molting, but since I am the one checking on their growth and keeping them, I caught the old skins left on the leaves.
During the molting period, which lasts about 24h, they don’t feed or move a lot - the japanese say they are “sleeping”.

The timings for this type of events, be the molts, the hatching or cocoonings, are not mathematic. When we started with this silkworm breeding I had time expectations that didn’t match the reality. Silkworm development can be faster or slower according, for exemple, with the variety of the animal, the amount of food available, room temperatura and overall stability in rearing conditions.
Our, it seems to me, have been slower in developing, although they grew well and steady.

[27.04.2015 / This post refers to the investigation and activities developed during the Saber Fazer em Serralves program]