Fig. 2. Search time for bumblebees to find the first flower in the flight arena during a 20-bout evaluation of foraging efficiency. Illumination conditions were changed just prior to the 11th foraging bout. Five different bees are used in each of the three test conditions; values are means ± S.E.M. (A) Mean data for five bees searching for 26 mm star shaped model flowers initially in UV+ and then UV–conditions. (B) Mean data for five bees searching for 15 mm model flowers initially in UV+ and then UV–conditions. (C) Mean data for five bees searching for 15 mm model flowers initially in UV–and then UV+ conditions.