Absconding of honeybee colonies and its prevention

Beekeeping in the tropics
How to start beekeeping in tropical areas

(lecture for a NECTAR presentation, 1998)

Introduction

In Africa honeybee colonies nest in the wild and are also kept in hives. Both feral and kept colonies abscond, naturally and by disturbance.

Several researchers and beekeepers decribe absconding for Africa: Lamb (1929) and Lumley (1928) in Smith (1953), Smith (1953 and 1960) and Fletcher (1975 and 1976). Winston et al. (1979) describe absconding for South America, where the Africanized honeybee colonies abscond unlike the European colonies which rather die in the hive.

Exhaustion of food stores in a nectar-less season is mentioned as the general cause, while lack of water and overheating are mentioned for the dry season of East Africa. However, if food stores are present in the hive, and water is available, the bees will stay. (Lamb, 1929 and Lumley, 1928, in Smith (1953)). When the water dries up the bees will consume all the food stores and abscond, to migrate to better areas. Combs are left behind empty, but sometimes even brood and food are left. Pests trigger the absconding, but do not seem to be the real cause.

Absconding rates are given by Fletcher (1975) for South Africa 15-30%, but sometimes even 100%; Winston et al. (1979) give 31% for the absconding season in French Guiana, South America; drones disappear before the absconding season and are not present in absconding swarms; most absconded colonies survived in the empty swarm boxes which they occupied.

Adjare (1984) reports for Ghana that foraging activity diminishes and the bees begin to consume the honey prior to absconding, while the queen stops laying eggs. The colony waits with absconding until all brood has emerged; the combs are chewed off before absconding; unnessary harassment is also a cause and probably some disease, perhaps a virus, which would be the cause of brownish powder in the combs.

Mutsaers (1992b) mentions the flattening of combs: cell walls are eaten off and comb edges are bitten off, which may reduce the combs up to 30%. She suggests that combs are an adverse condition for the colony in a decreasing nector flow. The brood nest and food stores are reduced in size, but the combs are not. Empty cells, unlike full cells - which are flat - have to be cleaned internally in order to control pests, like hive beetle (Aethina tumida) and waxmoth (Achroia grisella). This daily, intensive cleaning prevents flying out of the bees, so that foraging decreases.

Absconding occurs either by seasonal conditions inside the hive or by disturbance, as categorized by Winston et al. (1979) plus a combination of the two. Malmanagement of colonies may later in the season cause natural absconding. (Mutsaers 1992a and b).

Weighing and inspection of bee hives

From April 1990 until July 1993 hive weight was measured monthly in the apiaries of Ibadan and Ayepe, southwest Nigeria. In Ibadan the most important nectar flow is from August until march with a peak in January, caused by the flowering of the forest. This peak may be preceded by a smaller peak in October, when (cultivated) cassava (Manihot esculenta) flowers. A minor peak occurs in April-May. In Ayepe there are two major peaks. One is in February, like in Ibadan. A second is in May-June, when tree cassava (Manihot glaziovii) is in flower.

Weight of Bees and Combs (WBC) was calculated as the difference between occupied and empty hive weight. Hive inspections provided the number of combs (NC), number of queen cells, surface area of worker brood, drone brood, bee bread and honey, as well as information on pests. The number of bees (NB) was calculated as the difference between shaked-off combs and weight of bees and combs (WBC).

Results and conclusions

Honeybee colonies abscond when they fall under a critical weight of 3 kg in a decreasing nectar flow. Empty combs trigger this condition. To prevent absconding harvesting should be such that the colony will not fall later below this critical weight. One or two full honey combs should be left at the side of the brood nest. If the colony stays above a weight of 10 kg at the lowest point, it will develop faster in the next season, produce an early season honey and several swarms. Honey production and number of colonies, i.e. occupation of hives, will increase. If colonies are not harvested, they will have large areas of worker brood until long in the dearth season. They even keep their drones for a long time. Drones are a feature of wealth in an honeybee colony!

Weather conditions like low air humidity in the dry season affect bee behaviour and flowering of the vegetation. The flowering collapses and the bees stay inside the hive. There is a zero nectar flow when relative humidity falls below 50%.

Shape of hive. Thriving of colonies is possible both in traditional hives and modern - movable comb - hives. However, if the hive can only be opened in a way that harvesting means disturbance of the whole nest, including brood combs, then absconding after harvesting is unavoidable. Some beekeepers report that they smoke so heavily that the bees abscond before harvesting, hang temporarily in another tree and return into the empty hive. So the bees start with nothing, just the honey which they suck out of the combs before absconding. They use this to build the first combs in the empty hive. But if the brood would have been left inside the hive with some honey as well, they could have had a flying start and thrive even better in the next season.

Size (volume) of the hive. A colony which will fill up the hive before the peak of the season, should be harvested before the peak in order to prevent swarming. If a colony swarms it will be reduced in size and colony composition will change. (Winson et al., 1979). The number of bees is reduced and for some weeks there is no egg laying. The average weight combs decreases more after the peak. This sets the conditions for absconding later in the dearth season. Hoarding, as suggested by Winston et al. (1983), to survive dearth in the tropics, is not favourable as the surrounding nest will be occupied by pests which damage the combs, unlike in temperate climates.

If a hive is full at the peak of the season, the weight of the colony in kgs is about half the volume in liters: a hive of 60 liters will contain a colony of 30 kg. Of this maximum weight 90-95% is then honey (with a density of 1,45 kg per liter), while less than 10% consists of bees. If the hive is full before the peak of the season, the brood area is larger and the number of bees is relatively higher too. The hive is too small and the colony is forced to produce swarms. In any case, the colony could not develop fully, which affects production and sets conditions for absconding later in the season. Harvesting before the peak often means disturbing of the brood nest!

Prevention of absconding

New colonies which settle too late in the season will not make it, and are best combined with others. Colonies should always be kept as big as possible. Colonies should be harvested modestly, according to the expected season after the harvesting, and smaller colonies should not be harvested at all. In a decreasing season, empty combs should be removed when the colony is still strong. Hives should have a volume, according to vegetational nectar flow, between 80 and 150 liters. Traditional hives should have an opening at the back side, for inspection and harvesting, far from the brood, which is positioned near the bee entrance. Hives should be set in a good vegetation. Weighing of colonies can be a help to know the seasons and different weather types in one to a few years.

Honeybee husbandry is meant to have a higher production than from the wild. Understanding and reduction of absconding leads to increased production.

References

Adjare, Stephen. 1984. The Golden Insect. A handbook on beekeeping for beginners. TCC, University of Science and Technology, Kumasi, Ghana.

D.J.C. Fletcher (1975). New perspectives in the causes of absconding in the African bee (Apis mellifera adansonii L.) Part I. South African Bee Journal 47 (6): 11-14.

D.J.C. Fletcher (1976). New perspectives in the causes of absconding in the African bee (Apis mellifera adansonii L.) Part II. South African Bee Journal 48 (1): 6-9.

Mutsaers, M. 1992a. The development of a seasonal beekeeping method in southwestern Nigeria. Paper presented at the Fifth International Conference on Beekeeping in Tropical Climates. IBRA, Trinidad & Tobago, 7-12 Sept. 1992.

Mutsaers, M. 1992b. Absconding of honeybee (Apis mellifera adansonii) colonies in southwestern Nigeria, related to the seasonal weight of bees and combs. IBRA, Fifth Int. Conf. on Apiculture in Trop. Clim., 7-12 Sept. 1992, Trinidad and Tobago.

Mark L. Winston, Gard W. Otis, Orley R. Taylor, Jr. , 1979. Absconding behaviour of the Africanized honeybee in south America. Journal of Apicultural Research 18 (2): 85-94 .

Mark L. Winston, Orley R. Taylor and Gard W. Otis, 1983. Some differences between temperate European and tropical African and South American honeybees. Bee world, 64 (1): 12-21.

Thomas D. Seeley and P. Kirk Visscher, 1985. Survival of honeybees in cold climates: the critical timing of colony growth and reproduction. Ecological Entomology 10, 81-88.

Smith, F.G. , 1953. Beekeeping in the tropics. Bee World, 34 (12) 233- 245.

Smith, F.G., 1965. Beekeeping in the tropics. Longmans, London. 265 pp.