In article , Jaques
d'Alltrades writes
The message
from Kay Easton contains these words:

I understood amynthas to mean that in some species the ova wouldn't have
to be fertilised - not totally unreasonable? Don't greenfly do something
similar?

I don't think so. The clitellum passes down the worm - or to be more
exact, the worm squeezes through the clitellum and would collect sperm
from the vesicula seminalis before encapsulating the egg(s), though I
don't know whether it has been observed.

I've since spoken to him. He's not talking here about reproduction after
sexual congress, he's talking (as I understood from his post - "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. ") about certain species of earthworm who,
as well as indulging in sex, can also reproduce without sex. Since they
" don't bother with meeting
up with another worm and just produce cocoons from which identical
copies of themselves emerge" then the whole 'squeezes through the
clitellum" bit isn't relevant.

He tells me there are some species where specimens have been kept in
isolation since birth, and have still managed to produce offspring.
--
Kay Easton

Edward's earthworm page:
http://www.scarboro.demon.co.uk/edward/index.htm