Fig. 5.

Behaviour and proboscis extension of flying workers when lactic acid concentrations or sucrose were offered. EP stands for Extension of the Proboscis. Letters indicate statistical differences: a and b showed a significantly higher proportion of bees expressing avoidance toward lactic acid at 150 mg/mL; c and d showed a significantly higher proportion of bees expressing several extensions of their proboscis toward lactic acid at 1.5 and 25 mg/mL; e and f showed a significantly lower proportion of bees expressing a neutral behaviour toward lactic acid at 25 and 150 mg/mL. Black bars represent 95% confidence intervals (N = 30 honey bees/concentration except for sucrose N = 51 honey bees).