FLIGHT TONE OF FIELD-COLLECTED POPULATIONS OF ANOPHELES-GAMBIAE AND ANOPHELES-ARABIENSIS (DIPTERA, CULICIDAE)

Laboratory colonies of the human malaria vectors Anopheles gambiae Gil es and An. arabiensis Patton have distinct flight tones. If flight ton e similarly distinguishes natural populations of these sympatric sibli ng species, it may play a role in reproductive isolation of swarms tha t are otherwise behaviourally identical. To assess the fidelity of fli ght tone differences in natural populations, flight tone was measured in the Fl progeny of mosquitoes of both species captured in western Ke nya. Flight tone distributions of wild An. gambiae and An. arabiensis were similar to their laboratory conspecifics. However, interspecies c omparisons of flight tone of wild mosquitoes revealed significantly di fferent but overlapping distributions for both sexes. Furthermore, whe n the effect of body size on flight tone was determined, there was a p ositive correlation between wing length and flight tone for both sexes of An. gambiae and An. arabiensis, suggesting that mosquito size is a significant variable affecting flight tone. Although these findings d iminish any practical benefit of flight tone as a diagnostic tool in s pecies identification, its potential role in pre-mating species recogn ition needs further investigation.