Madeleine Pym wrote:
 
> My father was told by someone at the National Honey Show here in the UK this
> autumn, that some researchers in Germany have suggested that it is not the
> queen that fertilises her eggs but the workers. They are suggesting that the
> workers collect the semen from the queen and deposit it themselves,
> presumably in the cell, after the egg has been laid.
 
There are several facts that suggest that the queen fertilises
the eggs herself (e.g. v. Siebold, 1856).
 
However, unfertilised eggs can be fertilised some time later (up
to about 4 h). One can even do it by hand for breeding purposes!
There were several good articles into this subject
in the 'Deutsches Bienen Journal' (3/95, 3/96, 4/96, 8/96).
 
 
A study by Dr. Koeniger (1970) nicely demonstrated that
the front legs of a queen are involved in a queen's
'decision' whether to fertilise or not to fertilise an
egg. When both front legs are amputated (at the trochanter
= part of an insect's leg near the body) queens laid about
89 % fertilised eggs in drone cells. Amputation at more distal
parts of the front legs resulted in lower frequencies of
fertilised eggs in drone cells.
 
The author suggests that sperm release is the 'normal'
status and that drone cells block the release. He speculates
that queen cells do not contain this inhibiting stimulus
of drone cells and therefore eggs laid in queen cells
get fertilised.
 
The exact mechanism of sperm release is still unclear.
Besides the hypotheses Aaron Morris mentions (pressure),
there are two main other hypotheses:
According to Bresslau (1905) and Adam (1912) the muscles of
the sperm pump allow or inhibit sperm release.
According to Flanders (1950) the sperm pump is just a valve
that opens when an egg passes by, and it is the release of
fluid from the spermathecal gland that enables fertilisation.
If the gland's fluid is not released the egg remains unfertilised.
 
 
Paul Nicholson wrote:
 
> Either way, she's got to have a pretty effiecient
> mechanism to allow fertilization with her finite supply of sperm, yet also
> allow fertilization to be skipped.
 
A recent study by Ratnieks and Keller (1998) investigated the ploidy
status (fertilised eggs -> diploid; unfertilised eggs -> haploid)
of eggs. ALL 169 eggs taken from worker cells proved to be
fertilized, ALL 129 egg taken from drone cells were (most probably)
unfertilised.
 
 
And again: the queen fertilises eggs with sperm from different
drones in a random manner. The hypotheses that she first uses
only sperm from one drone exclusively, then from another
drone, and so on, is not true. I did a study into sperm usage
which I mentioned earlier on this list.
 
Hope I could help to clarify some things.
--
Michael Haberl
Hessische Landesanstalt fuer Tierzucht, Abt. Bienenzucht
Erlenstr. 9, 35274 Kirchhain, Germany, 51n 9w
Tel: ++49-6422-9406-12
Fax: ++49-6422-9406-33
[log in to unmask]