It's all in the diet

A couple of years ago I visited two abalone farms. Abalone are endangered species in Canada so it is difficult to farm them as you need to distinguish a wild abalone from a farmed one. The researchers at these farms had found a way to distinguish a live farmed abalone from a wild one by creating stripes on its shell. For a few weeks (or was it months?) they would feed them a particular plankton which created a yellow tinge to the shell as it grew. Then they would change the feed to a plankton that created a reddish tinge. Over the year this switching created red and yellow stripes on the shell. Seemed like a good solution. The problem was that one can't tell the providence of an abalone that has been separated from it's shell. End of the farms.  

[Image: Dr Natalia C. Tansil from New Scientist]

You are what you eat.  
Which brings us to a news item this week--silkworms. Various types of silkworms produces different shades of silk from white to a golden tan. The cocoons are reeled and spun and the resulting fibre is dyed. Some of these dye process produce terrible by-products and often harm the environment. But recently researchers have found that by feeding the worms mulberry leaves (their normal diet) that had been dyed, in their last four days before they cocoon themselves, that when they spin their cocoon with their silk, the silk takes on the colour of the dye. This supposedly will reduce the need to dye the silk...although it means they have to dye the mulberry, so I am not so sure we have solved something, just switched what is dyed. But the idea is interesting. Apparently they are now considering adding other compounds to the diet, things like antibacterial components for creating the silk that is used in medical procedures, like suturing. Hmmm, pink stitches.