It is almost two weeks since the silkworms arrived at Reading as first or early second instar larvae.
The larvae feeding on mulberry leaves are now entering the fifth and final instar, and some are over 5 cm long and about 7mm in diameter. I’m trying to rear them now at about 23C, which is a bit difficult as the rearing room, with assorted fridges and freezers, is not well ventilated and tends to build up heat. Still, I can keep the door open.
In the practical last week some people asked me what the moulted skin looks like, and I have a couple of photos below which shows this.
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Unfortunately, the larvae feeding on artificial diet fared less well last week. Although I was careful to move them onto new food and sterilise the containers, many died. I moved some more on to mulberry leaves, and they seem to be growing now, but although some of the remainder on artificial diet were growing and had entered the fourth instar, most were not and seemed to die during moulting.
Thus, yesterday I decided to kill these larvae and preserve them while I still could, so that there are at least some demonstration silkworm larvae available in the coming years, if we cannot get live silkworms.
It will now be a race for the silkworms to complete growth before the mulberry leaves become unsuitable: yesterday there were not many leaves that were still green, and I picked most of them. Also, I will have to prepare the mountages for them to spin their cocoons.