An explanation for some differences in behaviour between races of honeybees

Bee World No. 1, 1983, contains an interesting article by M. Winston, O. Taylor and G. Otis of the University of Guelph, Canada, who describe, and suggest explanations for, the variations in behaviour shown by European, African and "Africanized" honeybees.

There are no honeybees which are native to either North or South America. In North America the honeybees which are now present are of European origin, and these are suited to the temperate climate there: like honeybees in Europe, they can be well managed, and swarm only during one season each year. However, European bees introduced to the tropical areas of America have not been so successful. In 1955 some honeybees from South Africa were therefore’ taken to Brazil; the idea was to try crossing these bees with some European bees which were already there to get more productive hybrids. This experiment had an unintended sequel: 26 queens of the African bees escaped, and they certainly proved to be well suited to the tropical climate; from these few queens have descended the estimated 10 million colonies of "Africanized" bees now present in South America and parts of Central America. These "Africanized" honeybees still share the characteristics of .African honeybees, being difficult to manage because of their "bad temper" and their great tendency to swarm and abscond.

Other differences between temperate European and tropical-African and Africanized honeybees are that honeybees which evolved in temperate climates tend to build larger nests, about twice the size of those of tropical bees, and store much more honey. The temperate- European worker bees themselves are also larger, take longer to develop, and live longer than honeybees evolved in a tropical climate.

The article suggests ways in which different races of honeybees are Suited to the environments in which they live. For example, it is necessary for bees living in a temperate climate to behave in a way that will ensure the Survival of the colony throughout the winter. The temperature of the clustering bees must be maintained through winter, and this requires energy obtained from honey stores. Honeybees which live in temperate climates have therefore. evolved the habit of living in relatively large colonies, capable of building up the necessary honey stores. Such bees also tend to nest inside a fairly large cavity, giving them protection from the cold. In contrast, colonies of tropical bees do not require large honey stores and can therefore afford to live in relatively small cavities, with less stored honey. The species Apis dorsata and Apis florea do not even live inside a cavity, but nest in the open.

The authors draw attention to the two methods by which bees can survive a poor season; either they can hoard food to last until supplies are again available, or they can migrate to another area where food is still available.

For bees living in a temperate area, hoarding is the only means of survival; migrating is impossible in winter. Also a swarm of bees living in a. temperate climate can survive only if it leaves the hive early in the active season when there will be sufficient time to build up adequate honey stores to survive the next winter. Tropical bees do not face this constraint, and in some places can swarm throughout the year.

The greater tendency to sting shown by African and Africanized bees may be due to the larger number of honeybee predators present in the African tropics than in other zones. Frequent swarming and small colony size may also help to offset the harmful effect of predators.

The shorter development time of African and Africanized worker bees corresponds with the need for a rapid colony development and high swarming rate, whereas a longer life allows European workers to survive the winter,

From such arguments it can be understood why European bees have been difficult to establish in many tropical areas. Unfortunately, characteristics which have evolved to ensure the survival of the honeybee are not always advantageous for the beekeeper.

Some differences between temperate European and tropical African and South American Honeybees. M.L. Winston, O.R. Taylor and G.W. Otis. Bee World 64, 1, pp 12-21, 1983.