8.2. Roundabout construction
Several issues need to be considered, when a researcher wants to construct a roundabout for measuring honey bee flight behaviour:
- The arm of the roundabout should have a length of about 14-16 cm, so that one revolution equals roughly one meter.
- The arm should be connected to the stand as frictionless as possible (Fig. 18A).
- A circa 10-mm-long spur pointing downwards is needed at the end of the arm to attach the bee via a connecting tube.
- The spur must be moveable in all directions to adjust the bee's position (angle) before flight.
- The roundabout should be placed in a containment with regular (2.5 cm) vertical black and white stripes to provide a homogeneous optical flow during flight and an opening that allows manipulation of the bee.
- Mount a 60 W bulb on top of the roundabout as a light source and for adjusting temperature (ambient temperature affects metabolism and flight speed (Hrassnigg and Crailsheim, 1999)).
- Maintain the temperature (e.g. 28°C) throughout the experiment and when testing different groups.
- Register every rotation of the roundabout electronically (e.g. by a light beam).
- Collect data of the duration of every round in seconds and possibly of temperature at regular intervals.
- Flight time can either be derived automatically (computer program that clocks the time when the arm of the roundabout is in rotation) or manually.
- Because the arm may continue to rotate for a few rounds after the bee has stopped, we recommend to clock manually.
Fig. 18A. Construction of a flight mill (Drawing: Kurt Ansperger). B. A honey bee worker is attached to the spur of the arm of the roundabout, holding a ball of paper. Note that the spur can be moved in all directions to find the best position and angle for the flying bee.