In message , Jaques
d'Alltrades writes
The message
from Amynthas contains these words:
In message , Jaques
d'Alltrades writes

Whilst re-potting a miniature rose, I found a hell of a lot of these:
Cocoons are laid one by one as the worm moves through the soil,
not in masses. I've only found occasional ones, never great piles of
them.

If you look at my description of how they are formed, you'll see that
there is but one sphere full of fluid, which will mature into a lot of
tiny worms.

See below, 1 cocoon produces 1 earthworm even when there are
several ova in it. Some of the ova do not complete their development.

Your memory is a bit hazy. Earthworms lie head to tail with the
male pores of one opposite spermathecal pores of the partner (and visa
versa).

I'll quote one of the bits you left out of my reply:

Worms are hermaphrodites, and they lie together 'top-and-tail', secured,
IIRC, by each squeezing under the clitellum of the other. (The short
'sleeve' about a third the way from the front.)

The clitellum is not critical in the exchange of sperm. What is
important is that the male pores (on one of the segments about 15 - 18
depending on family) are lined up with the spermathecal pores (on
segments about 5 - 8 according to species and family).

Sperm is exchanged and they go their own happy ways. Later over
periods weeks or months, each worm secretes a cocoon from the clitellum,
The worm retreats out of the cocoon, depositing into it ova (eggs) and
sperm from the female and spermathecal pores respectively. Fertilization
takes place in the cocoon but, although several ova are deposited only
since worms have been seen to emerge.

I take it you mean single, not 'since'? I've been potting up some things
in once-used compost and have a plethora of these eggythings. I'll pot
some up in isolation and see what emerges, and how many of them.

Just make sure there are no earthworms in the compost (they can
be very small an elusive) and that there is no way for an earthworm to
get into the compost, 10 minutes in a microwave should be sufficient to
sterilise it. Then seal the pot completely in cling film. Come to think
of it, what ever hatches out will be difficult to see, so use only s bit
of damp blotting paper in a glass jar and check it daily.

I don't think they're slugs' eggs and they are certainly not snails'
eggs, and in the habitat of a flower-pot that doesn't leave room for
much else.

Well 20 years of experience as a research scientist working on
earthworms tells me that they are not earthworm cocoons.

.....or coccoons.

Of course, there are some worms that don't bother with meeting
up with another worm and just produce cocoons from which identical
copies of themselves emerge. (Come to think of it I don't think anyone
has checked whether the offspring are completely identical at the DNA
level.)

It's not the same as cloning: the ova would still have to be fertilised,
and as the sperms and the ova only have half a set of chromosomes each,
but with several options for the lining-up of many genes I'd guess that
the chances of the parent giving rise to identical copies of itself
would be slim.

That was probably a bit loosely worded. What I meant was that
there was only a single parent involved.

(Ref. another plaice: Where have you got to these days?)

Lots of places, mainly up in the Dales (and underneath them).
But very little time to read newsgroups.
--
Amynthas