Variation in learning speed (<i>t</i> values) of bumblebees from the six colonies in the initial and reversal learning phase of experiment 2.

<p>High values of <i>t</i> correspond to slow learning bees, whereas lower <i>t</i> values indicate faster learners. In each box the thick horizontal bar is the colony median, whilst the lower and upper edges represent the 25% and 75% quartiles respectively. Whiskers indicate the maximum and minimum values that are not outliers. Outliers are represented by open circles, extreme values by asterisks. The number of bees tested in each colony (N) is displayed along the x-axis, and colonies are ranked by increasing 75% quartile values from left to right. Variation in learning speed for the initial phase is shown in panel A, and for the reversal phase in panel B.