From my experience the depth of brood comb is always the same (at least for a give size bee SC or LC) regardless of the spacing. Just the honey gets drawn out more or less. I have not noticed a change in depth because of a change in spacing except for honey.
>Anyway, I thought there were some intriguing points raised in the article and that some might find it interesting, regarding spacing, cell depth, cell size, etc.
It is interesting reading and they have some interesting ideas.
This is just above what you quoted.
"The size and shape of the brood cells
The diameter of the worker cell appears to affect the invasion of
varroa mites. In the absence of drone brood, the varroa infestation
rate has been reported to be 16-50% lower in the small Africanized
worker cells than in the larger European (Italian) worker cells
(Guzman-Novoa et al. 1999, Rosenkranz 1999). This in part may
have been due to a higher visitation rate by nurse bees as the
European larvae were larger and heavier, and to the longer periods
spent capping the larger cells which would increase the time period
over which a mite can invade the cell (Message and Goncalves
1995)."
And a bit further down:
"No differences in larval attraction between Africanized and
European worker brood have been reported in laboratory or
colony trials (Rosenkranz 1999, Beetsma et al. 1999) suggesting
that there are no, or only slight differences between strains of A.
mellifera."
And:
"Several workers (Message and Goncalves 1995, Guzman-
Novoa et al. 1999, Ruttner, et al. 1984, Rosenkranz 1999, Medina
and Martin 1999) showed low rates of mite fertility: 40-50% in
worker brood of Africanized and European bees in Brazil and
Mexico. In these studies female mites entered worker cells but did
not lay eggs. However, this effect was worker brood specific as
about 90% of mites entering drone cells of Africanized bees were
fertile (de Jong 1997)."
IF there is little difference besides cell size between the two...
And this:
"Worker Africanized bees usually have a post-capping period 20
hrs shorter than European bees (Rosenkranz 1999). However,
among European bees there is significant variation in the average
duration of the capped period and this is a heritable characteristic
(Harris and Harbo 2000), but it can be affected by climatic conditions.
European Apis mellifera carnica bees had a worker postcapping
time only 8 hrs longer than Africanized bees at the same
tropical site (Rosenkranz 1999).
The model predicts that, in order to bring about a 25% reduction
in mite population growth (excluding the possible effects of
reduced mating success and fertility of daughter mites) the postcapping
period for worker brood needs to be reduced by 7% (20
hrs) for worker brood, by 9% (30 hrs) for drone brood and by 7%
(20hrs worker, 24hrs drone) for both. This results in a post-capping
time close to the minimum reported for worker brood, but
drone brood has greater phenotypic variation (de Jong 1997) suggesting
that it may be possible to breed bees that produce drone
brood with a shorter post-capping period. Buchler and Drescher
(1990) reported that 25% of the variation in mite populations in
their colonies could be accounted for by variations in the post-capping
period, which fits in well with the results of our model.
However, in a survey of European bees an average 8.7% reduction
of mite infestation rate was calculated for each 1hour reduction in
the capping time (de Jong 1997). This is a much larger effect than
our model predicts, suggesting other factors are confounding the
comparison in European bees."
Shorter capping times are what I suspect are the reason for small cell successes.
All in all the paper is interesting, but it still makes a lot of assumptions. But to make a mathematical model you have to simplify things.
