You are here

Acoustic biodiversity in tropical cicadas: examples from S.E. Asia [abstract]

Matija Gogala (1997). Acoustic biodiversity in tropical cicadas: examples from S.E. Asia [abstract]. Bioacoustics, Volume 8 (3-4): 250 -251



It is well known that the singing cicadas in S.E. Asia show very high biodiversity, with many species inhabiting the same ecosystem. They have to cope with the problem of sending their acoustic messages in a very noisy environment, since many insects, birds, frogs and other animals are emitting sounds at the same place and the same period of the year. Therefore the cicadas have developed their special strategies to cope with the jamming problem. One peculiarity is the evolution of songs with characteristic rhythmic patterns and in many cases even with a high degree of frequency modulation. The second adaptation to the extreme biodiversity is the fixed time of singing. Many cicada species are acoustically active only during a certain species specific time period of the day. Such a time window is usually 30 to 60 minutes long. Many species are singing only in the evening or only in the morning hours. Nevertheless, the dawn-dusk species are an exception in the Malaysian peninsula. Such time sharing between different species is probably not the only reason for "dawn'' "dusk'' or even "midnight cicadas''. This could also be an adaptation to avoid or minimize predation by birds or some other insectivorous animals. It should not be overlooked that many other cicada species there are not limited by a specific time window. Anyway, in the high biodiversity of S.E. Asia it is not difficult to find exceptions or special cases, and this is true also for the singing of cicadas. Therefore, the repertoire of the sound emissions of the S.E. Asian cicadas is challenging for every sound recordist. With suitable equipment nowadays it is not very difficult to make good documentary recordings there, despite high humidity. The main problem is still to see, identify or even catch the singing animals in the dense vegetation, and to find out the ethological context of the recorded sound emission.