Temperature

Temperature is EXTREMELY important in a bee hive.

There is quite a bit of research that shows a warmer hive is healthier for bees.

A healthy hive should have a hive temperature of 35C or 95F.

I reviewed the scientific literature to see HOW sub-optimal temperatures affect honeybee brood health.

Here is what I found. Stunning really.

Temperature in nature:

Bees normally live inside a hollowed tree. The walls would be 4-6 " thick. Thick walls would mean:

* A warmer hive during winter. Thus, bees would use less food/energy stores to heat their home to 95F.

* A cooler hive during summer heat. Again, bees would use less food/energy stores to cool the hive to 95F.

Less varroa with higher brood temperatures:

Here are three articles that support this concept.

A. Velthuis, Hayo H W, Kraus, Bernhard, 2000.

The Impact of Humidity and Temperature Gradients in the Brood Nest of Honeybees on the Reproduction of Varroa jacobsoni: Laboratory Observations, Second International Conference on Africanized Honey Bees and Bee Mites, 10-12 April 2000, Tucson.

Summary of results:

- reproduction of varroa decreases as temperature in brood cells increases

- varroa's optimum temperature to reproduce is 33 C

- optimum temperature of bee brood nest is 35 C

- peripheral comb is usually 33.5 C, good for varroa growth

(I have not found a website URL for this article. If you want a copy, send me an email.)

C. Derek and Elaine Mitchell from the UK have done 2.3 million mearurements on 8 types of hives to test hive insulation and its effects. Here is what they found.

Higher temperatures:

- hinder varroa breeding

- suppress nosema

- suppress chalk brood

- promote grooming behaviour

Higher humidity:

- increases bee egg survival

- hampers varroa breeding

https://oxnatbees.wordpress.com/2015/01/25/warm-hives

(submitted to Journal of Apicultural Research)

PAPER:

"Colony Mass, Thermal Conductance Ratios of Tree and Mand-made nest enclosure of Apis mellifera: Implications for Survival, Clustering, Humidity Regulation and Varroa destructor"

http://dx.doi.org/10.1007/s00484-015-1057-z

Published in the International Journal of Biometeorology, 3 September 2015

By Derek Mitchell, MSc derek.mitchell@eigentek.com

Summary:

Trees are 4-7X warmer than common hives in use.

When hives are thin the heat transfer rates are 4-7X higher than a traditional tree trunk with thick walls.

A warmer hive implies increased humidity levels in the nest, higher survival rates of bees and Varroa destructor having a harder time surviving.

So is there other scientific information on the effects of sub-optimal brood temperatures on honeybees? Lots.

It makes sense that bees would need more honey to stay warm in winter in an uninsulated hive.

Is that where most of the energy is used in a hive?

Jurgen Tautz answers this question with the following data.

40% of all energy to heat the brood. Wow.

Apparently Feb, Mar, April are key months as brood numbers are large compared to the number of bees to keep them warm + cold outside temperatures.

We know that uninsulated houses use more energy to heat them.

Even Langstroth himself knew of the importance of a warm hive.

In Langstroth's original book from 1853, he lists 50 suggestions for a good hive.

Look at what #2 was below.

Here is more research.

We know that pesticides are not good for anyone to eat.

But, interestingly, the effect of a pesticide depends on whether the hive is warm or cold.

So now I have my answer.

Cold brood chambers are challenging for bees.

Living in the warmth of an insulated tree trunk is good for bee health.

Any way of insulating your hives all year round would benefit the bees.