Picture: inside the hive of
a Trigona colony
There are about 20 000 species of bees known
all over the world, but of these only about 500 are `social'
bees; all the rest are solitary - they do not form colonies
and the females work alone. Excluding the subsocial bees
and the bumble bees (which do not occur in Africa south
of the Sahara), all social bees are placed in the family
Apidae, and in Africa these include the well-known honey
bees and the little stingless bees.
The stingless bees, also known as `mopane
bees' or `mocca bees', belong to the genus Trigona. They
are tiny; indeed some of them, at only about 3 mm long,
are among the smallest of all bees. They cannot sting. because
their stings are vestigial and useless as weapons of defence;
so instead they swarm out of their nest if disturbed and
buzz about in front of one's face in a verv irritating way,
settling in the hair and on the eyebrows and forehead, crawling
into eyes, mouth and nose and generally being very unpleasant.
On some occasions they bite freely. They nest in hollow
tree trunks and in holes in walls or rocks. The ground-nesting
species also use readymade cavities, such as termite nests.
An unusual nesting site of one African Trigona species is
in the nest of a cocktail ant.
The nesting material, usually dark coloured,
is called cerumen. It is a mixture of light wax and large
amounts of resin gathered by the bees. The wax is produced
between the dorsal segments of the abdomen, unlike the honey
bee which produces it from the underside. The cerumen is
used to block up cracks and crevices and also in the construction
of the curious spout or funnel that marks the entrance to
the nest. It has been suggested that the sticky funnel at
the entrance prevents ants and other unwanted visitors from
entering. Sentries remain on guard at the entrance during
the day, as is the case with the honey bee, but at night
the stingless bees close up the funnel with a temporary
plug of wax and gum.
The interior of the nest of stingless bees
consists of a brood section and a section for the storage
of food. In the nest of Trigona gribodoi, a well-known,
minute, tree-nesting species of Africa, the brood portion
consists of irregular clusters of oval-shaped cells and
cocoons, supported by slender pillars of cerumen. The cells,
vertical and open at the top, are first filled with food
and then closed after an egg has been laid erect on top
of the food supply in each one. Therefore these little bees,
although they are social, rear their young in very much
the same way as the solitary bees do. The large storage
pots, which contain pollen and honey are up to 7 mm in diameter,
and made from soft cerumen, yellowish to brownish in colour.
Both the honey and the brood of stingless
bees are relished by Africans. The honey is usually sourish
and thin compared to that of honey bees, but it can be just
as tasty, depending on the species of stingless bee and
the source of the nectar. On rare occasions they may make
honey from Euphorbia flowers, and since the plant is known
to be poisonous, Africans regard this honey as poisonous
At the top the nest, which is lined with
a mixture of cerumen and mud, is connected to the outside
by a more or less vertical passage. Below the nest is a
second passage like a pipe, half a metre or more in length
and which simply ends in the ground. This acts as a drain
pipe for any water that may reach the nest. Within the nest
cavity the brood area is enclosed in laminated sheets of
cerumen, separate from the storage pots. The brood cells
are arranged in layers, to form a more or less spiral comb.
The bees make a store of sticky cerumen
in the nest chamber near the entrance tunnel. This is to
trap any insects that attempt to invade the nest, and puts
them out of action.
Dactcylurina staudingeri is unique among
the stingless bees in that it makes vertical, double-sided
combs, like those of the honey bee. It is found in Central
and East Africa, where it makes cerumen-covered nests under
the branches of large trees. When disturbed the bees attack
in large numbers, carrying lumps of very sticky cerumen
which they glue onto their foe, biting at he same time.
Even determined humans are soon demoralized by this treatment!
This information was copied from an excellent
book: African Insect Life S.H. Skaife, revised edition
by John Ledger, Struik Publishers, ISBN 0 86977 087.
Well worth buying if you are interested in African insects.