Biomedical Engineering Reference
In-Depth Information
2.2.3
Pyramid for Catching Bees
A pyramid (height 24 cm, apex 3.5 × 3.5 cm, base 18 × 18 cm) made of UV-translucent
Plexiglas is useful to catch bees when leaving the hive and fl ying towards the sky.
This is why the Plexiglas has to be UV transparent, in order to offer a complete view
of celestial cues and thus lure the departing bees within the pyramid. The pyramid
is closable at the apex and at the base. For catching bees, the pyramid is held at
about 10-20 cm distance in front of the hive entrance with the base open and the
apex closed. Bees will naturally enter the pyramid when leaving the hive. When
enough bees have been caught, the base should be closed and the pyramid taken to
the laboratory. When the pyramid is darkened (except for its apex), bees will exit it
through the apex because of their positive phototaxis. Given its pyramidal form, the
bees will tend to leave the pyramid one by one, thus facilitating individual capture
and precluding mass escape. This allows transferring the bees from the pyramid
apex into glass vials.
2.2.4
Harness Tubes and Tube Rack
Harness tubes (major diameter 10 mm, height 32 mm) can be made by cutting cyl-
inders. Materials can be metal, plastic, acryl, etc., as far as it suits the experiment.
A rack with numbered boreholes would be useful for handling and identifi cation of
harnessed bees. Each harness tube should be numbered to allow individual identifi -
cation of the bees throughout the experiment. When placed in the tubes, only the
bee head should protrude, thus hiding other body parts from possible contacts with
later sucrose stimulation. The forelegs of the bees, for instance, should not be able
to move free but should remain enclosed without the tube in order to avoid uncon-
trolled cleaning of mouth pieces and antennae during the experiment which may
interfere with olfactory and sucrose stimulation.
2.2.5
Odorants
The choice of odorants should be made according to the main purpose of the experi-
ment. Both single chemical compounds (alcohols, aldehydes, terpenes, etc.) and
mixtures of compounds (rose extract, carnation extract) have been used in such
experiments (see Sandoz
2011
). It should be noted that the use of some odors as
conditioned stimuli, like pheromones, which are potentially important in the bee's
biology, may induce a potential bias when used in experiments on learning and
memory. Likewise, possible prior experience of bees with some odorants (in the
hive or while foraging) may also affect the results. Such responses indicate that
the bees may have already learned this odorant in an appetitive context before.
