Fig. 2.

Brain dopamine (DA) levels in 2-day-old worker bees. (A) QMP exposure reduces levels of dopamine in the brain. (B) Young hive bees exposed to a mated queen show lower brain dopamine levels than those exposed to a virgin queen. (C) Reduction of brain dopamine levels after exposure to HVA. (D) Brain dopamine levels are not affected by exposure to HOB. (E) Reduction of brain dopamine levels from exposure to HVA and HOB combined. Data are expressed as means ± SEM. Numbers in each bar represent n values. P values show the significance of differences between groups as determined by two-tailed Student's t tests.