The Chemistry of Silkworm Eggs

I am getting a satisfactory collection of eggs. These change colour as they age. When they are laid they are a creamy white, they then become yellow, then brown then grey. The seem to harden too. I am keeping them warm and humid, and once all the moths are dead (though only one female has died so far) I am going to treat a few of them with hydrochloric acid.



Silk worms come in several types, and one way to distinguish them is by how many times they breed in a year. In temperate places they tend to breed just once, or more commonly twice, a year to coincide with the leafing of their only food-source, the mulberry. These are called monovoltine or bivoltine respectively. In tropical regions the silkworms tend to be multivoltine. The eggs take only about 10-12 days to hatch because the mulberry is in leaf all year round. Multivoltine silk tends to be inferior to bivoltine silk - being thinner, more variable and shorter. So a common practice in India is to hybridise the silkmoths with the hybrids having the favourable characteristics of both parents.

Unfortunately I have no idea what sort of silk moths I have. If they are bivoltine they might need to be kept for a few months in cool conditions. However it is possible to speed things along by washing them in hydrochloric acid. This destroys the enzyme present in the temperate silkworms that inhibits their development in the egg. So I think I will experiment with just a few and see what happens.