Thursday, July 18, 2013

Hive Ventilation and Cooling

To determine why some Ethiopian beekeepers are experiencing bee colonies absconding, or abandoning their hives, we look at each of their three types of hive. Honey bees will abscond if there is not enough forage in the area, and then the bees migrate to areas where food is available. This dearth of forage does not seem to be severe enough in some of the areas experiencing absconding. Honey bees will, however, abandon their hive if environmental conditions make the hive completely unsuitable for bees and developing bee brood. After evaluating the Ethiopian traditional hive, the transitional, or top bar hive, and the modern bee hive for size, ability to shed rain water, and ease of defense, we look at the ability of the bees to regulate hive temperature and provide ventilation. Here, we see several problems with the hive designs and the bees’ ability to maintain their hive’s internal environmental conditions. The traditional bee hive, usually constructed of cane, coated with mud or dung, and wrapped in banana leaves, is often plugged so that only a tiny opening exists for bees to enter and exit the hive. There is almost no through-ventilation inside the hive or space for bees to fan their wings at the entrance. The same lack of ventilation exists with both transitional and modern bee hives. Modern Zander bee hives, like the ones shown in today’s photo, are particularly lacking in through-ventilation. A small entrance is the hive’s only outside port. Air circulation in the top of the hive is difficult to maintain. Fortunately, this ventilation problem can be easily solved by cutting a screened hole in the back of the hive.

Beeswax melts at temperatures around 145 degrees Fahrenheit, and there are reports of wax melting in Ethiopian bee hives. Since bees try to maintain a brood nest temperature around 95 degrees, such wax-melting hive temperatures make these hives completely unsatisfactory. Shade trees and hive stands with elevated roofs protect hives from the tropical sun.
--Richard

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