The secret of Isopods without eyes- Part 2

From

Frank

08.03.20

It’s been a few months since I got the all-white Isopods. I have therefore been able to do some research on this species and observe it extensively. The color mutation is more or less known as Porcellio scaber “White Out”.

In the first article, I discussed how Thomas Hunt Morgan experimented with fruit flies and white eyes. He discovered a gene that was linked to the color of the eyes and the sex of the fruit flies. Because of this discovery, I was concerned that this mutation would only occur in the male sex.

If you haven’t read the article yet, you can do so here:

Das Geheimnis der Asseln ohne Augen

So I wanted to take the next opportunity to examine the sexes in this mutation and see if both sexes were present. And indeed, I was able to discover a brood pouch (marsupium) in an Isopod. This was the first step in disproving that eye color was linked to sex.

Geschlechtsbestimmung, Paarung und Fortpflanzung von Asseln

A nice breeding group quickly developed from the 5 animals received. Only 2 gray animals emerged. The mutation was therefore quite color stable and we only had to select very rarely.

The behavior of Porcellio scaber “White Out” does not differ from that of other isopod species. They like to eat the skin completely after moulting and use it as a source of calcium.

Now we come to the question of what color the Isopods’ blood is and whether a pigment is actually necessary for the white eyes or whether they are simply transparent. Vertebrates have red blood. The red color comes from the red blood cells that transport oxygen. That’s why we humans sometimes have red eyes in photos. This occurs when the flash hits our eye at a certain angle. This makes our blood vessels visible in the eye and they appear red.

Arthropods and molluscs, which include our Isopods, have developed an alternative to our blood. It is called hemocyanin (from the Greek häm, ‘blood’ and kyanos, ‘sky-blue’). The name tells us quite a lot. Hemocyanin is colorless. However, if oxygen is transported, it has a sky-blue color.

This confirms that our Porcellio scaber “White Out” has white pigmented eyes.

During my research I came across a new Porcellio scaber mutation. It is called Porcellio scaber “Lucy”. The appearance is white, like our Porcellio scaber “White Out”, but this mutation has black eyes. Now the question arises whether the white eye color can be transferred to other Porcellio scaber color variants, or whether it is genetically possible to transfer the black eye color to the Porcellio scaber “White Out”. I will therefore continue the project and cross different color variants with each other.

You’ll find out how I’m going to do this in the next article.