CLUSTERING EXPERIMENT: DONE BY JACK DARLEY AND BERTRAND ROEHNER
AT MEUDON VAL FLEURY (WEST OF PARIS, FRANCE) IN JUNE-JULY 2012

 Experiment of 15 June 2012, 14:40-16:10

Animal: bees (Apis mellifera, Linnaeus, 1758

Objective: It is of course well-known that bees cluster in
winter time or before swarming (that is to say when one
part of a colony is about to leave the beehive with its queen).
In the present experiment we wish to study the clustering of bees
without any external stimulus. How long will it take?
What is the influence of population density?
Such experiments were pioneered by Mr. J. Lecomte
in the early 1950s as documented elewhere on this website.

Size of the box: 39cm x 50cm. As there were 305 bees,
each of them had a square area with a side length of 2.4 cm.
The depth of the box was only 5.5 cm and it was permanently covered
with a transparent plactic sheet (PVC or polyvinyl chloride, 0.5 mm
thick). In addition an opaque cover was put in place between the
moments when the pictures were taken.

The temperature was 20 degrees.
After about one hour the bees had formed a cluster on the right-hand
side which comprised 83% of them. This situation remained unchanged
for 20 mn, then within 5 mn the cluster moved from the right- to
left-hand side. The number of bees which were not included
in the cluster remained almost the same at a level of 15%.

A picture was taken every 5mn.

This experiment was part of a series of 9 experiments 
performed with bees. They 
are fully documentated elsewhere on this website.