The Varroa Experiment


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Object

The object of the following experiment is to prove conclusively
that the varroa population in a colony of honey bees is limited
sufficiently by natural grooming and hygienic behaviour by the
bees, to enable co-habitation, without any other form of treatment.

Theory for Bee Population

1.	During the winter (mid Oct-Feb) the queen lays no eggs.
2.	During March-May the queen lays continuously about 1000 eggs per day.
3.	About 2000 drone eggs are laid mid April.
4.	Bee numbers increase from 10,000 to 40,000
5.	The colony swarms once at the end of May.
6.	This results in a two week gap in egg laying.
7.	The new fertile queen commences egg laying at 1000 per day for 
        about 9 weeks, then in reduced numbers for a further 9 weeks 
        spanning the period mid June to mid Oct.

Theory for Varroa Population

1.	During the winter period Oct-Feb, when the bees and varroa
	are dormant, there is no grooming.
	The varroa drop during this period is the result of bees dying
	and the dead bee and the live varroa fall to the floor, where
	the live varroa dies.
	About 1/3 of the bees die and 1/3 of the varroa follow suit.
2.	During March - May there is little grooming if the bees are
	over stressed and under these conditions the varroa drop
	during this period consists mainly of the remaining 2/3 dying
	from old age.
	If the colony started the winter with 300 mites, 100 would
	drop Oct - Feb and the other 200 March - May.
	March - May gives the varroa 13 weeks of perfect breeding
	conditions.
3.	Allowing a female varroa 3 cycles of 2 weeks in cells breeding
	and 2 weeks outside resting, breeding 1 viable daughter in
	worker brood and 2 viable daughters in drone brood, 200 varroa
	become 1,800 during this period and can show a daily varroa
	drop of only 2.
	Having 200 mites on the 1st March with the queen laying around
	1,000 eggs per day on natural comb, during the second week all
	200 varroa should have entered cells.
	They would be 'in phase', so in week 3 all varroa would be
	inside cells and none observable outside.
	If the offspring followed suit this would be repeated during
	weeks 7 and 11 etc.
	This could explain swarms free of varroa when the hive is
	heavily infested.

4.      During the 2 weeks of varroa nest site absence, caused by the 
        swarm issuing at the end of May two things occur. 
        (a). Varroa are more active, looking for nest sites, and therefore
        more vulnerable. 
        (b). Many nurse bees are available for grooming. At this time
        about 50% of the varroa lose their lives due to this situation. 
        When nest sites become available, multiple mite infestation 
        causes cells to be uncapped. The mother survives but has lost 
        one of her three reproduction cycles and becomes 'out of phase'. 
5.      During mid Aug - mid Oct brood rearing is much less and 
        grooming and uncapping much more and the varroa gradually become 
        further and further 'out of phase'. 
6.      The daily varroa drop eventually equals the daily varroa birth
        rate and a balanced situation occurs and the varroa population 
        stabilizes. 
7.      When all egg laying has ceased, the mites exiting cells have to 
        remain outside continuously and are now liable to be groomed 
        until the bees cluster and the varroa take up their 
        over-wintering mode. During this period the groomed varroa are 
        not replaced and if the varroa drop in Sept was 400 per week 
        indicating a balanced situation of 1,600 varroa and the winter 
        varroa drop figure was 5 per week, this would suggest that the 
        last 4 weeks of large varroa drop figures are irreplaceable and 
        equal to about 1,300 varroa. 
8.      There is therefore no over all increase in the varroa population 
        on an annual basis.

Method

During the year 2000 a number of swarms were collected and housed in 
'GM' and 'HT' hives. The experiment will be conducted with three of 
these hives numbers 11, 13, and 15 which appear to be of similar strength.

Hive No 11 was collected on the 4th June from Blackmore End. 
Hives No 13 and 15 were collected on the 7th June from Halstead and 
Hawkwood respectively. 

Each week commencing from the 4th Feb the floor debris of each hive 
will be inspected. 
The number of varroa will be recorded and the presence of dead embryo 
bees (worker & drone) will be noted. 

It is intended that any swarms from these hives will also be monitored 
for weekly varroa drop etc. 

Samples of dead bees and varroa from these hives are available upon request. 
It is the expectation that the results, yet to be obtained in the forthcoming 
year, will show that the varroa population, in an untreated hive, does not 
follow an exponential curve. 
It is also hoped that the reason for this apparent phenomena will be made 
clear by the results following the varroa population theory.

The results up to the current time are shown below- 04/02/2001 - 06/02/2002
Notes from the author at each monthly update <READ NOTES>

The graphs will be updated 4 weekly. Conclusions made in December 2001.

Picture (above) shows natural comb inside an 'HT' hive

Author: Ian Rumsey Address: Morris Green Farm,
        Sible Hedingham, Halstead, Essex, C09 3LU
Email:  ianrumsey@hotmail.com
Notes from the author at each monthly update <READ NOTES>

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