Varroa Life cycle .. details of timing
The Module 3 (extremely useful) study notes provided by the Mid Bucks Beekeeping Association include a diagram of the varroa life-cycle, on page 16, which states that “Time taken from egg to adult for males is 5-6 days and for females is 7-8 days”. These numbers are widely repeated on information pages about varroa, often together with the beautiful illustration drawn by Byron Alexander (below).
 |
| Illustration from Byron Alexander[1] (possibly from
Henderson,
C, J. Steiner and B. Alexander. 1986. Varroa jacobsoni life cycle; American Bee Journal 126:117-119.
|
But
… in Honey Bee Pests, Predators and Diseases (Morse and Flottum) different numbers are given: 5.5-6.2 days
for males and 6.5-6.9 days for females. These numbers are backed up
by an article by Collinson
(http://www.beeculture.com/a-closer-look-varroa-mite-reproduction/
) which gives 3 references (Donzé and Guerin 1994; Martin 1994; Rehm
and Ritter 1989) for time to maturity from egg of 5.8 and 6.6 for
male and female respectively.
Also … the 7-8
days to maturity for a female egg does not add up: if the mite lays
the first male egg after 60 hours, and then a female egg 30 days
later, and then we add 8 days for reaching maturity .. this would
take us to almost 12 days for the first female mite maturing. To get
1-2 female mites maturing before the worker brood emerges we need a
maturing time closer to the 6.5-7 time range.
The idea that a
female mite takes a full 2 days longer to reach maturity than an
adult is also inconsistent with the diagram on page 15 of the study
notes.
Hence, I believe the shorter time of 6.5 to 6.9 days for a female to reach maturity looks more likely than the 7 to 8 days suggested by the B. Alexander illustration.
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1: More about Byron Alexander: https://archive.org/stream/entomologicalcon00byer/entomologicalcon00byer_djvu.txt
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