Information on measuring hive performance

As with most science, results from experiments have to be mulled over to find the thread of truth. I have not the time or ability to manage this. Here are some research & its conclusions. Results can be quite contrary because there are so many variables. For example:

There is an optimal cluster size for over-wintering and this presumably depends on the:

  1. local climate and its variability

  2. strain of bee

  3. colony character

  4. amount and type of insulation and distribution between walls, roof, and floor

  5. hive ventilation

  6. type of ventilation

  7. direction and site of hive entrance(s)

  8. orientation of the frames

  9. volume and proportions of the hive etc.

  10. insulation, type, thickness etc.

User of stores can be three times larger or half as much in insulated hives presumably depending on:

  1. Brood rearing

  2. Bee mortality

  3. Bee longevity

  4. Pollen stores

  5. Climate and weather

  6. Bees leaving the hives

  7. Characteristics of the cluster etc.

Honey production?

  1. Colony size

  2. Climate etc ….. I get the idea that there are so many variables to consider, and past research is often sloppy and descriptive.

Winter losses: are similar or (more usually drastically) lower in insulated hives: consider factors that should be considered:

  1. Colony size

  2. Disease status

  3. Number of bees

  4. The effect of bee deaths on other bee deaths, etc.

Examples of research regarding Hive insulation

1. Heat loss from various types of enclosure occupied by bees.

Derek Mitchell (UK, 2015) Lumped enclosure thermal conductance (WK−1) Cedar Warré hive 1.28, Simulated tree cavity 0.47

Clearly, the Warré hive is vastly inferior in terms of heat retention compared with a tree cavity.

2. Ratios of colony mass to thermal conductance of tree and man-made nest enclosures

re: Apis mellifera: implications for survival, clustering, humidity regulation and Varroa destructor. Int J Biometeorol DOI 10.1007

3. Importance of hive insulation for wintering, development and honey yield in Norway.

Apiacta 9:277–281 Villumstad (Norway, 1974) Villumstad compared store consumption over winter and a couple of other performance features in hives with three different wall thicknesses:

Double walled 60 mm 8.5 kg Double walled 45 mm 9.8 kg Single walled 22 mm 11.8 kg

Thick walls reduced consumption of stores.

4. The thermology of wintering honey bee colonies

Owens, C. D. (1971) Bull. U.S. Dept. Agric. 1429: 1-32.

A study over five years studying characteristics of cluster in relation to temperature. He found that insulated colonies produced brood in sub-zero temperature. A cluster held for long periods under freezing conditions declines in strength. The rate of decline is dependent on pollen stores available, and is slower in insulated than in unprotected colonies.

5. Weight of overwintering hives

Mobus (Scotland, 1998)

Mobus placed an insulated and an uninsulated hive on recording scales and monitored weight loss over one winter from 19 October to 25 February. In the uninsulated hive, the loss was double that of the insulated hive.

Temperatures against the walls, even remotely from the winter cluster, are always higher than the ambient (outside) temperature. Double wall and insulation resisted heat outflow. There is a thermal gradient showing that there is heat loss from the only source of heat in the hive, namely the cluster. This loss is made at the expense of honey. Note also that when the ambient temperature falls below zero, the inside hive environment is cushioned against this drop.

6. Hive type and over-wintering

Dodologlu et al. (Turkey, 2004)

These authors compared 36 polystyrene and 36 wooden Langstroth hives as regards a number of wintering parameters. The wooden hives had 25 mm thick walls and the polystyrene hives 30 mm thick walls. 5 of the colonies in wooden hives died and 12 of the colonies in polystyrene hives died. Polystyrene hives consumed much less food (6.2 v. 8.6 kg). The decrease in the overwintering population was greater in the polystyrene hives. The authors suggested that the lower food consumption in the polystyrene hives is due to their higher overwintering loss of bees.

In contrast to the Dodologlu study, Genersch et al., analysing 4,313 colony winters found no difference in losses between wooden and polystyrene hives, 11% in both cases.

7. Productive management of honey-bee colonies II.

Olszewski (Poland, 2007) American Bee Journal 328-330 113 (8): 288-290; (10): 373-375; (11): 415-417.

Olszewski found overwinter, deaths in poorly insulated hives were two and three times greater than in insulated hives. Furthermore, depending on bee breed, uninsulated colonies consumed 19- 24% more 'food stores'.

8. Estimation of the usability in apiculture of styrofoamed hives on pallets.

Marcinkowski J., (1985) Zeszyty Naukowe (Poland) XXIX, 169-185.

Marcinkowski studied colonies over three winters in polystyrene hives and wooden hives. Food consumed was 7% lower in wooden hives, but the results were very inconsistent from winter to winter. There were more dead bees in wooden hives in all three winters, but the styrofoam hives were noticeably wetter. There was a slightly higher rate of Nosema in the wooden hives. Ambient temperatures dropped to -12 °C over the winter but remained more than 2 °C above freezing in the polystyrene hives, dropping to only -1.2 °C in the wooden hives.

9. Overwintering and hive packing

Haydak (Minnesota, 1958)

Haydak experimented on hundreds of colonies over 10 winters and showed that 'heavily packed' hives showed dramatically lower winter losses with packing: 18.4% as against 2.9%.