By Ole Hertz, Denmark
Death’s head hawk moths present a seasonal problem for beekeeping in Cape Verde. They are known in Cape Verde as Bambalutas: Latin name is Acherontia atropos. The moths are large (about 7 cm long) grey/brown in colour, and with beautiful yellow hind wings. They are named after the pattern on their thorax, that resembles a ‘death’s head’ or skull pattern. Acherontia atropos occurs in a few areas of Europe and Africa: other species of Acherontia are found in Asia. The green larvae feed on the leaves of potatoes, tomatoes and other plants. The adults feed mainly on sap from tree wounds.
After the rainy season, which in Cape Verde means several days of showers in the autumn, bambalutas can be seen in great numbers. The bambalutas are attracted to the smell of honey and will wait around near the nests of bees and also try to enter hives.
If a large number of bambalutas get into a hive, the bees may be so disturbed that they will abscond. The bees will sting and kill some bambalutas, but their numbers can be so great that it is impossible for the bees to keep them out. The moths that are killed in the hive are embalmed in propolis by the bees and are found in large numbers inside the hive. Many moths get stuck in the hive entrance and sometimes it becomes completely blocked by the moths.
During an earlier beekeeping project in Cape Verde a special screen was invented to place in front of the hive entrance. This allows the bees to enter the hive and prevents the large bambalutas from doing so. Some moths still manage to get into the hive at the entrance and through any other cracks and gaps.
These screens are needed for the few months during which the bees are constantly under stress from the attempts by the moths to get into the hives. This problem is particularly bad at night when the moths are at their most active, and it is easy to hear that the bees are upset.
In the ‘bambaluta period’ a thick layer of dead, unpleasant smelling bambalutas are found in front of the hives with dust from their wings filling the air. The live bambalutas land in great numbers on beekeepers working with the bees. If you grab a bambaluta it produces a loud whistling sound. For bee and human health reasons the beekeepers should remove the dead bambalutas.
It is a mystery how the wild bee colonies avoid the bambaluta problem. Often the entrance to the nest is so small that the moths cannot enter or the colonies are so high in the mountains that the bambalutas cannot thrive.
This will be the objective of research during the Danida-funded project. We will experiment with new types of hives with ventilation in the top to attract the moths and to keep them away from the hive entrance.
[Bees for Development Journal #60]