Beekeepers:

In a prior post on this subject I mentioned looking at the figure on p. 140
of the Webster/Deleplane book Mites of the Honey Bee and had convinced
myself that it would not be possible for mites to reproduce within a queen
cell. Today, I looked at it again and now realize it was previously being
looked at incorrectly.

The books I have (Webster/Deleplane: Mites of the Honey Bee and
Morse/Flottum: Honey Bee Pests Predators & Diseases) say mites generally
enter  cells approximately 20 hours and 40 hours for worker and drone
larvae, respectively. At this time the larva has completely covered the
cell bottom and mites immerse themselves in the liquid larval food beneath
the grub. Roughly 30 hours or 1 1/4 days after cell capping, the first male
egg is laid and will develop into an adult within about 5.5 to 6 days.

The queen larva, I think,  has covered the cell bottom by the sixth or
seventh day. On the eighth day the queen cell is capped. If a mite enters
the queen cell and begins laying 30 hours after capping 9 1/4 days will
have passed. Adding the 6 day period for the male  to reach maturity puts
the time interval time at 15 days. Given that the queen will normally
emerge in 16 days, it looks to me as though there is adequate time for the
male varroa mite to develop.

Female eggs are laid at about 25 to 30 hour intervals after the first male
egg. Adding the 30 hour interval to the 9 1/4 days above gives 10 ½ days.
Females develop from egg to adult in about 6 to 7 days. Adding the higher
number of 7 days to the 10 ½ days will put us at 17 ½ days, or about a day
and a half past the time a queen would normally emerge. But here is the key
word–normally. Queens do sometimes, if I am not mistaken, emerge later than
the published figure of 16 days.

Now, let’s go back to the female and slightly compress numbers. Say, the
first female egg was laid 25 hours after the male egg. This would place the
time interval of queen development at 10 1/3 days. Using the slightly
smaller development of 6 days from female egg to adult will place both mite
sexes at maturity when the queen leaves her cell.

Suppose, the male varroa egg was laid a little less than 30 hours after
cell capping, and the female followed at a little  less than 25 hours.
Suppose now the queen emerged a bit past 16 days. Isn’t it possible then,
at least theoretically, for mites to actually reproduce within the queen
cell?

I would invite those who have the Mites of the Honey Bee book to take a
look at the figure given on page 140.  Look at the worker drawings. Move
the mite development up one tier since the queen cell will be capped at 8
days. Count down 17 days (for a late emerging queen) and you will see that
both sexes will reach maturity.

One final note: In a previous post a group member mentioned not being aware
of any documented cases of mites entering queen cells. I ran across this in
the slide script for the set of slides on Honey Bee Parasites, Pests, and
Predators put out by the MAAREC consortium. “Varroa mites have a definite
preference for drone brood; however worker brood also is attacked. Queen
brood is used only in cases of heavy infestation.”  Before anyone sniffs
and says that hardly qualifies as documented evidence, I will agree.
However, the individuals involved in producing the slides were Scott
Camazine, Dewey Caron, Maryann Frazier, and Diana Sammataro–all well known
names within the beekeeping community. I’m certainly willing to take a leap
of faith in regards to their statement.

Regards,
Dick