Diversity of sound-producing insects in a Bornean lowland rain forest

Abstract

In the canopy of a lowland mixed dipterocarp forest in Mount Kinabalu Park (Sabah, Malaysia), animal sounds were recorded for several weeks during the dry and beginning of the rainy season. Spectrogram analysis revealed clearly identifiable sound patterns which in most cases could be classified at the order level (crickets, cicadas, katydids and vertebrate sounds) and attributed to certain ‘ethospecies’ which in several cases could be caught and identified. Song activity of cicadas and birds was diurnal, while crickets started singing at dusk, followed by strictly nocturnal katydids. This indicates pronounced temporal segregation at the order level by diel periodicity. During sunset, overall sound intensity increases due to several species engaging in a ‘dusk chorus’ composed of chorusing cicadas, crickets and frogs. A distinct ‘acoustical guild’ is observed at waterfalls, showing special adaptations of call structure to high background noise. The value of acoustical records as a tool to assess local and regional diversity is discussed.