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Bioacoustic survey of cicadas [abstract]

M. Gogala & A. V. Popov (1996). Bioacoustic survey of cicadas [abstract]. Bioacoustics, Volume 6 (4): 300 -301



During the last two summers we recorded and analyzed songs of all species  of cicadas in Slovenia and lstria (Croatia), with the exception of Cicadetta montana. First, the TELINGA Pro III Stereo microphone and DAT recorders SONY TCD-D3 and TCD-D7 were used, giving good results in the sonic range of up to 20,000 Hz. Soon we recognized that a useful additional tool to detect songs of some smaller species was a bat detector. Songs of Tettigetta brullei (Fieber 1876), for instance, were not easy to detect with a TELINGA microphone from a distance greater than 2 to 3 meters, but with the bat detector (Ultra Sound Advice, S-25) we were able to detect its presence from at least 10 meters. Unfortunately, the microphone in this device is not directional enough to easily locate the singing animals. Therefore, this year we combined a parabola of TELINGA with the ultrasonic microphone of an S-25 bat detector, connected to the main unit by an extension cord. The signal from the bat detector was recorded with the DAT machine. Such a combination proved to be very effective and gave us new insights into the spatial and temporal distribution of small singing cicadas. We were able to detect and locate animals (e.g. Cicadivetta tibialis (Panzer 1798) or Tettigetta brullei from up to 50 or more meters away. With the help of this device we know that T. brullei sings in the Slovenian Karst from mid-June to mid-August, often high in the tree tops. One can count singing animals and estimate population densities, and in a short time it is easy to confirm also the presence of small species of cicadas (not only big and loud ones) in a certain biotope. Using an ultrasonic detector it was also easy to detect and record the previously undescribed songs of locally distributed Cicadetta mediterranea on the shore of the southernmost tip of Istria. It would be of interest to many of us if such a device combined with an ultrasound recorder could be built commercially to record the pure ultrasonic signal on one channel of a stereo recorder and the transposed one on the other.