BEEKEPPING
&
DEVELIOPMENT
31
DANCING AND TREMBLING WHEN A WORKER BEE finds
a source of nectar she informs other bees about it when she returns to the nest. They visit the nectar source and in turn inform others when they return to the nest. In this way forager bees are recruited to make efficient use of available nectar supplies It was Kar! von Frisch and his colleagues who, over many years, worked out
how the information is communicated by
means of the waggle dance.
As more bees visit the nectar source and return to the nest, so more bees will be recruited to visit the source But what will happen if so many bees are leaving the nest for the nectar that there are insufficient left behind to deal with all the nectar being brought in? Wolfgang Kirchner of the University of rzburg in Germany believes that another ace, the ‘tremble dance’ provides a negative feedback The tremble dance stops workers flying off for more nectar if too much is currently arriving at the nest for the foodstoring workers to cope with Wolfgang Kirchner studied bees in hives placed 10 m from a feeder with sugar syrup. As the number of bees at the feeder increased, so the proportion of bees performing tremble dances
Kirchner showed that worker bees subjected to these vibrations performed significantly shorter lasting waggle dances, and consequently the number of bees leaving for the feeder decreased. In this way the colony is able to ensure that it functions most efficiently: there is no point in foragers working to bring nectar which cannot be stored This research relates to the western hive bee, Apis mellifera
Behavioral Ecology and Sociobiology. 1993,
vol 33, page 169
THE WAGGLE DANCE The flowers offering nectar are along a line 45°C to the rialil of the sun as the bee leaves her nest
On returning
to her nest, to
commurucate the location of the flowers the bee ‘dances’ a figure of eight pattern on comb
the vertical) of the line along which she wagales lin Hus case 45°C) indicales the angle of the
nectar source to the sun. The duration of the waggle indicates the distance to the nectar source
Ae
7y\ sun
honeybee colony
45°
increased.
ge OL
The tremble-dancing bees produced vibrations at frequencies of 45-350 Hz, lasting for 142 milliseconds, which made the comb vibrate
'S§ BEES
within the nest. As she runs along the straight bit in the middle of the eight she 'waggles’ her body quickly from side to side The angle Uo
nectar source
IN ANGOLA
temperature constant subterranean existence. The largest of the stingless bees, Trigona bocandei, has produced 10-15 kg of honey in a season and the wax, which is often used to dilute ordinary beeswax, has certain properties which are being studied The hives in which the three species of these bees are housed at Luso are very complex and natural reproduce many of the features of the store not does colony As is well known, Trigona like a in but grouped in comb cups large honey bunch of grapes around the brood cells. The hives have drawers which are of the exact internal height to accommodate the cups, and in which Trigona obligingly build them. identical Attempts to persuade the bees to fill been rubber cups with honey have unsuccessful A feature of the culture of these bees which has not yet been considered is their habit of storing propolis and pollen in The size of separate cups along with the honey.
the cups enables the pollen to be eaten unspoiled by wax or honey and very good it is. Of the three species of stingless bee at Luso the smallest, Trigona landula, the ‘honey fly’ has proved the easiest to manage and a certain amount of information has been collected about it. Virgin queens are raised continuously by this species but are killed unless required. This enables the colonies to be propagated by splitting the brood. Generally Trigona seem more susceptible to temperature differences than honeybees, and make extensive use of propolis and wax to insulate the inside of their hives. Trigona landula mix their propolis with sand for this purpose while Trigona bocandei surrounds the brood and comb with paper-thin membranes of a wax-like substance. The queens are easily identified in all these
species.
Murray Armor
LETTERS TO THE EDITOR
Inspecting a hive containing
Trigona
stingless bees.
RIVE
