Well, here's a strange column about the famous creator of Astroboy (there's a photo of him looking natty in a beret) and his background in science. Previously thought to have studied medicine, it seems he might only have done a PhD in ... snail sperm.
Which leads the writer to then note his own experience in studying silkworm sperm. It's odd:
I was looking at another species with unusual sperm: the silkworm, an insect that has been bred for more than 5,000 years in China.
They are amazing animals. They have been bred for so long by humans that they have lost the ability to reproduce on their own: They require humans to bring them together. They have also lost the ability to fly. But they still beat their wings, and when they crawl over your hand, you feel tiny gusts of wind from their wings, like mini fans directed at your skin....
And here's why I briefly studied them: Like all butterflies and moths, silkworms have two types of sperm, produced in a roughly 50:50 ratio of ones with cell nuclei containing the DNA needed to fertilize the egg, and ones containing no DNA that are therefore unable to fertilize eggs. A sperm that can't fertilize an egg! What good is that?
Yes, when you raise silkworms at home, as I have done a couple of times with the kids (involving a drive every second day to a mulberry tree in a neighbouring suburb on a vacant block of land to fetch leaves), the moths that emerge look weak and pathetic as they merely flutter a bit and don't move much. But, in fact, this is normal.That's the mystery, and while there are lots of ideas — the best among them being that the dud sperm are used as some kind of soldiers to fight off the sperm from other males in order to give their DNA-carrying brothers a chance — there is no consensus on their function.
As you were....