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

Defensive Bee Behavior

Beekeepers describe honey bees as having a defensive nature. They are not described as being aggressive. Bee behavior is such that guards will effectively defend their hive from intruders. Guard bees check all incoming bees and turn away those from foreign colonies. The guards spread alarm pheromone to alert other worker bees anytime the hive is invaded by insects or mammals. The combined effect of numbers of stinging workers effectively defends the bee hive with its queen, brood, and food stores of honey and pollen. Even though honey bees may rush out of the hive to drive away an intruder by inflicting numerous stings, honey bees do not aggressively hunt or attack people or animals. Honey bees are quite docile while they are away from their hive foraging. Today’s small, black honey bees foraging for nectar and pollen completely ignore children playing around the decorative plant’s flowers. The honey bees of East Africa have a reputation for being among the most defensive bees in the world. However, many of the colonies are not highly defensive.

As part of my work in training Ethiopian beekeepers, I tried to encourage the farmers to work the bee hives gently in the daytime hours as opposed to their common practice of destructively harvesting the hives’ honey and beeswax at night after driving away the bees. Some beekeepers have good experiences and enjoy working their bees, and others seem to be reluctant to handling living bees. Only by examining bee hives in daylight can the beekeepers effectively observe the combs for brood diseases and other hive health issues. Our examination in Amhara of Ethiopia’s three types of bee hives finds that each is well designed to allow the guard bees to effectively protect the colony. Each hive has a small opening for an entrance, giving the guard bees the advantage of defending a small area. Ethiopia’s greatest bee hive pests are ants. Other invaders include wasps, hornets, birds, and small mammals including the honey badger.

--Richard

A Dry Bee Hive

For bees living near the equator, dry and rainy seasons shape the bees’ year. The month of June sees the beginning of a four month rainy season in Ethiopia’s Amhara Region. A bee hive must be able to protect the bees from the elements. The hive must be designed and mounted so that it is protected from rain. We examine each of the three Ethiopian bee hives to see if they are suitable in the rainy season. Traditional hives, though often covered with mud and dung, are usually wrapped with banana leaves, effectively shedding rain. Modern bee hives have a solid cover, making them quite rain proof. Only transitional hives, also known as top bar hives are vulnerable to rainy season problems. Traditional hives are mounted in trees, where they serve as effective swarm catchers. Some traditional hives are mounted on the walls of farmers’ houses, protected from rain by the overhanging thatch or metal roof. Modern and transitional bee hives are mounted on stands in the open. All three types of bee hives are at times mounted on stands with a covered roof as in today’s photo, which shows from left to right a traditional hive, transitional hive, and modern Zander bee hive. The roof above the hives provides for good rain protection as well as shade from Africa’s tropical sun. The space above the hives allows for good air circulation.

Bees in transitional hives are most vulnerable to rain. Top bars are usually covered with some protective material. If the covering is a simple water resistant top, the hive is well protected. However, it is a common practice in Ethiopia to cover transitional top bar hives with a heavy layer of green leaves during the rainy season. While this traditional practice is meant to protect the hive from rainfall, it tends to hold moisture in and around the hive. The moisture adds to the development of chalkbrood, a fungal disease commonly afflicting Ethiopian bee colonies.

--Richard

Bee Hive Size

Honey bees live in cavities. In Ethiopia, natural cavities are hollow trees or crevices in volcanic rock walls. Ethiopian farmers also keep bees in three distinct styles of manmade hives. Traditional bee hives are long baskets, usually constructed from cane or strips of wood. Transitional bee hives, also known as “top bar hives,” are open baskets with strips of wood at the top to hold the bees’ combs. Modern bee hives are wooden boxes with removable frames to hold the bees’ combs. Honey bee colonies will generally maintain their brood nest in a hive as long as there is food available in the region and the hive remains suitable to the bees. To try to determine why the Amhara beekeepers are experiencing their bees' absconding and swarming, we look closely at each of the three manmade bee hives.

The first concern for a bee hive to be suitable for the bees is its size. For the farmers to build up a population of bees capable of producing a surplus of honey the hive must be large enough for the bees to greatly expand their brood nest. In nature, bees often select a cavity with a volume of about 40 liters. After the colony fills this volume, the colony divides; and half of the bees swarm in search of another cavity. We measure traditional and transitional hives and find them to have a volume of about 89 liters. A modern Zander hive with two brood nest boxes measures about 84 liters, probably a suitable volume. It appears that the use of a single Zander brood nest box by some farmers probably leads to brood nest congestion and swarming. The Amhara farmers recognize that they might be able to reduce swarming by adding more hive boxes and frames as bee populations grow. In today’s photo, seasoned Ethiopian beekeeper, Gebeyehu, brings one of his traditional bee hives to the Machakel training facility for us to examine. Hive size is important wherever we keep bees.

--Richard

Honeycomb Walls

Ethiopia’s Amhara Region is a day’s drive northwest of the capital city of Addis Ababa. Farmers in Amhara, like farmers throughout Sub-Sahara Africa, rely upon honey bees to provide an important part of their farm income. They recognize that the honey bee alone has the ability to harvest pollen and nectar from forests and pastures and produce valuable products of honey and beeswax. The farmers of Amhara asked for assistance. I accepted the USAID-funded assignment of Winrock International to assist the farmers gathering at The Hunger Project-Ethiopia’s Machakel agricultural training facility. The farmers explained that when they harvested honey and beeswax, their product was judged to be of low quality; and their beekeeping added little to their incomes. Despite their best efforts, their honey and beeswax yields seemed to continuously dwindle. Those keeping bees for long periods expressed that beekeeping was easier and yields were greater 15 years earlier. In fact, many of the bee hives that farmers owned sat empty of bees. Many of the farmers blamed herbicides for killing their bees. While some herbicides are used by farmers in an effort to increase production on plowed fields, most fields in the Amhara highlands are plowed by oxen and cultivated by hand ax. Herbicides seemed to me to be an unlikely cause for the farmers’ plight. While herbicides kill weeds and reduce this source of forage for bees, the chemicals themselves are generally considered to be safe for bees.

The Amhara farmers also complained of their losing bees to two common activities of tropical honey bees: absconding from the hives and reproductive swarming. I felt like an investigation into the farmers’ bee hives and their beekeeping practices might help explain these losses. The agricultural fields of Ethiopia’s highlands are interrupted by two of the world’s magnificent river gorges, the Jamma and the Blue Nile. Approaching Machakel, rock walls built of six-sided crystals of volcanic columnar basalt line the paved road offering a honeycomb pattern to this land of bees.

--Richard

Rebuilding Winter's Losses

All of America’s bee colonies have been lost twice in the last six years. That is the effect of the 30 to 35 percent annual honey bee colony losses since 2006, the year Colony Collapse Disorder was identified. The Bee Informed Partnership’s “Winter Loss Survey 2012—2013: Preliminary Results,” http://beeinformed.org/2013/05/winter-loss-survey-2012-2013/, reveals, “On average, US beekeepers lost 45.1 % of the colonies in their operation during the winter of 2012/2013.” Beekeepers do not feel that annual colony losses of one third are sustainable. Surveys point to losses above 15 percent as being unacceptable. Beekeepers consider the labor costs and expenses involved in cleaning the hives of dead colonies and the resources consumed in rearing replacement queens and colonies. Anecdotal evidence indicates that individuals may experience losses well exceeding the average. One commercial pollinator states that he actually loses and replaces all of his colonies in a year’s time.

The USDA presents the report, http://www.usda.gov/documents/ReportHoneyBeeHealth.pdf, compiled from the October 2012 conference in Alexandria, Virginia of numerous stakeholders in honey bee health. These include honey producers, commercial pollinators, chemical producers, extension agents, researchers, and agents of the USDA and Environmental Protection Agency. The report provides an in-depth listing of current knowledge of honey bee health matters; and it offers a number of serious questions asking for further research. I hope that many of these will be addressed. The conference stakeholders address honey bee nutrition, pests and pathogens, pesticides, genetics, breeding, and biology. Best management practices are being explored. Teams of concerned stakeholders in honey bee health are gathering information, and beekeepers are working to rebuild colony numbers. Queen bees developing in queen mating nucleus hives will start new colonies to replace winter losses. A check of queen cells in today’s photo shows two queens emerged successfully from their peanut-shaped cells. The cell on the right remained closed; its queen did not emerge. The newly emerged queens will make mating flights and then begin laying eggs in two to three weeks.

--Richard

Treasure Valley, Idaho

Beekeeper Doug Cleveland and I sit by the wood stove of his Idaho wood shop and compare beekeeping in Idaho’s Treasure Valley with that in the Arkansas Delta. Doug is the president of the large and active Treasure Valley Beekeepers Club with commercial operators, sideliners, and backyard beekeepers gathering in Boise. Treasure Valley is protected by surrounding mountains. Although considerably farther north, the valley’s winter conditions are similar to those experienced in the Arkansas Delta. Treasure Valley, a high desert, supports a diverse agriculture through the use of an extensive system of irrigation canals that carry water from melting snow in the mountains. Throughout the valley, I see pallets of bee hives. Honey bees pollinate large fields of peas, beans, and mint. Treasure Valley spearmint is grown for its aromatic oil in 40 acre fields. Blue wooden boxes house alkali bees that pollinate alfalfa fields cultivated for seed production. The assembly points of commercial beekeeping operations today are littered with dead colonies. Recent reports show over-winter bee colony losses of 50 percent or more. See http://www.nytimes.com/2013/05/03/science/earth/government-study-cites-mix-of-factors-in-death-of-honeybees.html?hpw. Numerous factors seem to lead to the heavy losses of bee colonies, including queen failure, starvation, parasitic mites, winter weather conditions, Colony Collapse Disorder, pesticides, Nosema disease, small hive beetles, and general colony weakness. This US report comes as Europeans ban neonicotinoid insecticides, widely questioned as leading to honey bee colony decline. See http://www.nytimes.com/2013/04/30/business/global/30iht-eubees30.html. Having the systemic insecticides banned in Europe while extensively used in North America, there is the opportunity to make comparisons and study the effect these insecticides have upon honey bees. Let’s hope that independent researchers can learn from this two-year break in neonicotinoid insecticide usage.

Doug Cleveland and I share many beekeeping techniques. We both rely upon the hygienic behavior of resistant strains of bees to remove parasitic mites from the hives. We avoid harsh chemicals, and we both use thymol, derived from the oil of the thyme plant, to reduce colony mite loads. Today’s photo: Treasure Valley bee hives.

--Richard