Fig. 3. Response spectra recorded in identified glomeruli of the drone antennal lobe. (A) Amplitude of calcium responses (F/F%, positive signal 1 s after odour onset) to queen pheromone components and control stimuli recorded in the two macroglomeruli (boxed; mean ± s.e.m., N=11 drones). Only the major component 9-ODA induces clear calcium signals in MG2. MG1 does not respond. ^***P<0.001 for all pair-wise Scheffé comparisons. (B) Comparison of responses in three different regions (F1-3; boxed) of MG2 in a subset of the drones (N=5), to the queen pheromone components, the control stimuli and all floral odours in common for these drones. No difference is observed between the response spectra of the three foci: all respond specifically to 9-ODA. (HEX, 1-hexanol; LIO, linalool; ORA, orange oil). (C) Responses of two ordinary glomeruli (boxed) responding to the pheromone components HOB (ventral glomerulus) and HVA (central glomerulus), respectively, in the five drones in which these glomeruli were clearly seen. Responses to the queen pheromone components, the control stimuli and all floral odours in common for these drones are presented (NON, 1-nonanol; LIM, limonene; CLV, clove oil).