Measurement of flight tone differences between female Aedes aegypti and A. albopictus (Diptera: Culicidae)

Mosquito flight tone was amplified and digitally sampled at 20,000 samples per second (Hz). Resampling of the resulting sound files at 1,000, 5,000, and 10,000 Hz allowed comparison of flight tone frequency distributions for males and females of Aedes aegypti (L.) and A. albopictus (Skuse). Frequency distributions for females of the two species did not overlap at sampling rates of 5,000 Hz or higher, whereas considerable overlap was observed at the 1,000 Hz sampling rate. Males of the two species produced flight tones higher in frequency than those of females, but similar to each other. At the highest sampling rate, seven flight tone harmonics were measured for each species. Close correspondence of the means of the flight tone harmonics (corrected for harmonic number) demonstrated that any of the harmonics may be used accurately and precisely to calculate flight tone frequency. These data indicate that flight tone differences have been selected in these species and could act as an isolating mechanism for mating.