Box and whisker plots of the number of worker contacts (a) and their duration (b) towards cages that contain a virgin queen or a worker bee and towards empty cages. Boxes include the median and the 25th and 75th percentiles; whiskers give the fifth and 95th percentiles; dots represent outlying values; N denotes the numbers of experiments (a) or of worker contacts (b), respectively; total observation time = 180 min (60 min / cage treatment). There are no significant differences in the workers’ behavior towards the differently treated cages (Kruskal-Wallis tests; a: P = 0.739; b: P = 0.443).