Abstract:
The wide bandwidth EMR ultrasound, exploited in mosquito repellency, yielded only 20 % effectiveness. Due
to this wide bandwidth, ultrasound from Amolops tormotus and Coleura afra, mosquito predators, was investigated. The
sound was recorded, filtered and anaysed by Avisoftsoftware; transmission parameters determined and compared with those
of EMR. Spectrogramanalysis showed harmonics, FM and CFcomponents.The fundamental frequency ofA. tormotus and C.
afra sound was 5.371 kHz and 6.836 kHz respectively. The bandwidth of unfiltered sound of A. tormotus and C. afra was
10.98 kHz and 17.71 kHz respectively. The maximum peak amplitude of unfiltered sound of A. tormotus and C. afra was
135.19 dB SPL and 134.97 dB SPL; maximum acoustic energy was 19.57 Pa2
s and 35.80 Pa2
s respectively. Maximum
acoustic energy of A. tormotus and C. afra sound was 10.843 Pa2
s and 14.857 Pa2
s recorded in 35-60 kHz and 10-34 kHz
ranges respectively. Optimum acoustic parameters included 58.5 kHz peak frequency, 12.32-10.84 Pa2
s acoustic energy,
19.40-19.85 kHz bandwidth, 55.13-55.48 kHz and 34.66-44.26 kHz as mean maximumand minimum frequency respectively,
134.08-134.28 dB SPL peak amplitude and 132.06-133.27 dB SPL minimum peak amplitude; bandwidth significantly
narrowed from EMR. These parameters are critical in realizing effective EMR.
