Figure 1. Place preference assay apparatus.

Bees are placed in individual lanes, sandwiched between a Plexiglas® cover and a metal grid that is electrified (6 V, 50 mA) on one half. The halves have a color card placed under the grid. In this picture the yellow half is electrified and blue half is “safe”. Bees develop preference for the safe half, they show avoidance to the color side associated with electric shock. To prevent bees from walking upside-down and avoiding the shock, the Plexiglas® cover is coated with a thin layer of Vaseline, using a wipe. Bees are transported in 15 ml numbered culture vials and followed individually. Both manual records of position at every 15 secs and video recording and transcription are used for data collection.