Figure 6

Autofluorescence generated by benzaldehyde in the chemosensory hairs and the anterior margin vein of the Drosophila wing.

Flies were exposed to a high dose of benzaldehyde (50 μL in a 300 ml vial for two hours). (A) The anterior wing vein is fluorescent and the thin hairs corresponding to the chemosensory sensilla (thin arrows) are also labelled. (B) The photograph shows fluorescence in the chemosensory hairs but not in the stout bristles corresponding to the mechanoreceptors (thick arrows). The vein is intensely labelled. (C) Fluorescence obtained with a cut wing treated in the same conditions. The margin vein is weakly labelled, but the thin chemosensory hairs are not labelled at all. (D) Dose response of emitted fluorescence obtained with living flies (blue stars) after two hours of exposure to increasing concentrations of benzaldehyde. The fluorescence was measured in the anterior wing margin region delimited by the red oval in the box. Each determination is the mean + /− SE, n = 10. A relative measure of fluorescence obtained within the anterior wing margin of cut wings treated in the same conditions (red stars) is reported for two concentrations of benzaldehyde (mean + /−SE, n = 5). For 10 and 50 μl benzaldehyde, p < 0.01 and < 0.001, respectively, between the cut and living wings (Student’s t-test).