Recent behavioral findings in female yellow fever mosquito Aedes aegypti (L.) (Diptera: Culicidae) led us to investigate the electrophysiological response spectra of sensilla trichodea A2-type in more detail. This sensillum type houses two receptor cells which can be distinguished by their different spike-amplitudes in single-sensillum recordings. We have classified these receptor cells based on their odor-evoked response spectra to volatiles emitted from humans. These stimuli included the natural multicomponent odors breath and body odor as well as different concentrations of following single compounds, which have been found in human sweat: (1) L-(+)-lactic acid, the indispensable synergist for other attractive components in behavioral studies, (2) ammonia, and (3) n-aliphatic carboxylic acids with chain length from C1 to C6. Our results show several functional classes of receptor cells with distinct overlapping response spectra. These classes are mingled within the A2-type sensillum in varying pairs.

Index terms: Mosquito, olfaction, host odor, single-sensillum recording, sensillum trichodea.

---