Fig. 1

Chemical analysis of Drosophila headspace followed by electrophysiological screening of the candidate pheromone compound Z4-11Al. a Chromatograms of headspace collections from D. melanogaster (Dalby) females (lilac traces; upper trace: amplified signal; lower trace: entire chromatogram), males (blue trace), and D. simulans females (green trace). The headspace of D. melanogaster females contains 16 yet undescribed compounds: heptanal (1), octanal (2), (Z)-4-nonenal (3), nonanal (4), (Z)-4-undecenal (Z4-11Al) (5), undecanal (6), dodecanal (7), (Z)-4-tridecenal (8), tridecanal (9), tetradecanal (10), pentadecanal (11), (Z)-4-hexadecenal (12), hexadecanal (13), (Z)-4-octadecenal (14), octadecanal (15) and (Z)-4-eicosenal (16) (Table 1). Female-specific compounds are coloured, the most abundant cuticular hydrocarbon, 7-tricosene (17), is shown for reference, the internal standard (IS) was heptadecyl acetate. Inset: mass spectrum of the most abundant female-specific compound Z4-11Al. b Oxidation of the most abundant female cuticular hydrocarbon (Z,Z)-7,11-heptacosadiene (7,11-HD), affording two saturated and two unsaturated aldehydes, heptanal, hexadecanal, Z4-11Al and (Z)-4-eicosenal (Table 2). c Single sensillum recordings (SSR) from all D. melanogaster olfactory sensory neurons (OSNs) with Z4-11Al (error bars show SEM; n = 5). d SSR coupled to gas chromatography (GC-SSR), showing the response of ab9A to three different amounts of Z4-11Al