(A) Schematic examples of the diversity of floral temperature patterns in the sunlight. By using thermal imaging, Harrap et al. show that more than half of the species they tested have temperature differences within flowers that are big enough to be detected by bumblebees (color indicates temperature as shown in gradient). Experiments with (B) small and (C) large artificial flowers tested if bumblebees could associate a certain temperature pattern with a reward, in this case a sugar solution (blue cup symbol). Bumblebees were presented with two variants of temperature patterns, one containing the sugar reward and the other just water (top and middle rows). As a control, flowers without temperature patterns were used as both rewarding and non-rewarding flowers (bottom row). The position of the bumblebee in B and C shows which floral temperature pattern was visited the most after 60 visits, demonstrating that bumblebees were able to use these patterns to increase their foraging success.