Hi all

Trevor said...

> Also everyone seems to throw their hands up in horror when they find that
> some drones do not have a lot of semen.  Think about it.  Does it
logically
> follow that if a drone has a smller amount of semen than another, it will
> naturally follow that that semen will produce inferior offspring?

There are two aspects to this...
The first is semen amount.  Variability in semen quantity is natural and
does not concern me other than the purely practical fact of more loads of
semen need to be collected per insemination (in the case of small volumes)
and possible lack of genetic diversity in the case of larger volumes. The
crunch comes when the drones are dry, there are always a percentage of
drones (even those of calibrated age) that are dry, but the problem is
occurring more often and the percentage of dry drones appears to be rising.

The second aspect of semen volume per drone is coupled to what Trevor said
about mating frequency...

> We say that queens mate with 7 to 15 drones (varys on who you talk to)
> but why will one queen mate with say 7 and the next 15.
> Does she know that she has not collected enough semen,
> hence the variation in numbers?

I think the answer to this lies more in genetic diversity than in numbers of
sperm per spermatheca. In good weather mating, in drone assemblies the
figure of 7 -15 is about right. In poor weather mating and supercedure
strains the figure is more like 10 - 25. We know that this is not for volume
reasons, because the spermatheca is 1 - 1.1 microlitres and each drone will
produce around 1 microlitre. I think this is a mechanism that increases the
chance of diversity in situations where inbreeding is more probable. The
extra volume that is collected is expelled after some homogenising has been
done.

Another aspect of the document (that I have now read more thoroughly) is the
apparent correlation between clipped queens and sperm count. can anyone
throw any light on that?


Best Regards & 73s, Dave Cushman... G8MZY
Beekeeping and Bee Breeding Website
http://website.lineone.net/~dave.cushman

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