Fig. 5

Extents of amplification and frequency-specific response behaviour in spontaneously oscillating male receivers. a Flagellar displacements (2nd row from the top) and antennal nerve responses (3rd row) to pure tone stimulation (1st row) for an An. gambiae male following the onset of spontaneous SOs. The SO frequency was measured as 361 Hz. Red boxes highlight stimulus frequencies for which entrainment was judged to occur. Power spectra of flagellar displacements (4th row) for each stimulus frequency are included to visualise frequency-dependent changes in the receiver’s entrainment behaviour. b Frequency range over which individual male An. gambiae (GAM, blue) or Cx. quinquefasciatus (QUI, red) exhibiting spontaneous SOs entrained to pure tone stimulation of different frequencies. The frequency range is represented as the difference between the frequency of the pure tone stimulus itself and the best frequency of the SO. Individual data points indicate the entrainment status of each mosquito at each frequency measured, which ranged from ±300 Hz the difference between the pure tone stimulus and the SO best frequency with 10 Hz increments between each tone used. The shaded area, which covers a range of 30 Hz (i.e. ±15 Hz), represents the maximum region over which SO entrainment to the stimulus took place. Cx. quinquefasciatus males = 2; An. gambiae males = 3. There is no data for Ae. aegypti males as they did not show spontaneous SOs under our experimental conditions. c Diagrammatic representation of hypothesised effect of the male SO on electrophysiological responses of male JONs in the presence of the female flight tone. Power units and scale of responses are arbitrary. Solid green line represents electrical tuning for male mosquitoes, whilst the solid red line represents male mechanical tuning. SO=self-sustained oscillation, WBF=wingbeat frequency, cubic distortion=product difference between twice female WBF and male WBF, difference tone=difference between male and female WBFs