> peer-reviewed bit of research showing uninsulated cavities outperforming insulated cavities in any context.

This one was reviewed by DR. WALTER ROTHENBUHLER (who was peerless):

Bayles, V. R., & Parker, R. L. (1958). Winter protection of honeybee colonies in Kansas. Amer. Bee J., 98(9), 360-363.

The colonies during 1953-1954 were in two-story 10-frame hives while during 1954-1955 and 1955-1956 they were in one-story Dadant hives. Each treatment consisted of two adjacent colonies. Treatments consisted of colonies (1) wrapped in tar paper; (2) covered with a twolayered celotex overcoat type of packing case; (3) on summer stands with no additional covering but located within the apiary; (4) south side of the two rows of evergreens; and (5) north exposure, in the open, north of windbreak. Different paired colonies Each of the colonies the last two years were wintered in a one-story Dadant brood chamber.

The colonies covered with tar paper had the least average loss (6 lbs.) while the colonies with the two-layer overcoat case had the greatest average loss (30 Ibs.). The overcoat type case apparently keeps the colonies too cold in the spring and during warmer periods in winter because of the insulation which retards the temperature change within the hive, delaying brood rearing in the early spring resulting in a weak colony not able to take full advantage of the first major nectarflow or the collection of large quantities of pollen in the spring. 

Tar-paper wrap is thin and permits a more rapid change of temperature in the hive, and since it is black in color, absorbs the heat from the sun and thus raises the temperature within the hive, resulting in opportunities for cleansing flights during favorable weather in the winter and the initiation of brood rearing earlier in spring. 

On the basis of loss of weight during winter, it is concluded that among the protective materials used, winter protection in the area of Manhattan, Kansas, is best attained by use of tar-paper wrap and that overwintering without any protective insulation or covering is better than the two-layer overcoat case as used in these studies. On the basis of relative increase in weight of bees and sealed brood during early spring, no protective covering is better than tar paper, and distinctly superior to the two-layer overcoat case.

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