Slovenian Wildlife Sound Archive is a scientific collection of animal sounds housed in the Slovenian Museum of Natural History. The collection includes mainly original animal sound recordings on digital storage media (HD-s, CD-s, CD ROM-s, DVD-s, etc.), DAT-cassettes, analogue magnetic tapes and cassettes, which were made by researchers in the museum and some other collaborators. The primary goal of the archive is to collect the recordings of sounds and calls of all the animal species distributed in Slovenia, which are producing sounds. The research is focused mainly into the bioacoustics of Cicadas (Hemiptera: Cicadidae) in Europe , Asia Minor and SE Asia.
In the Slovene Museum of Natural History (Prirodoslovni muzej Slovenije) in Ljubljana – Slovenia exists a unit for Natural Audio and Video Documentation of Slovenia (NAVIS). One of the activities is the research in bioacoustics of insects, with a focus on true bugs (Heteroptera) and singing cicadas (Homoptera: Cicadoidea).
Here we represent typical calling songs of 9 species od cicadas, 8 of them found in Slovenia and 1 – Cicadetta mediterranea - living on the nearby coast of Southern Istria near Pula (Croatia).
Songs of some smaller species are high pitched, ranging into ultrasound (e.g.Tettigetta brullei ) and are not easily detectable by unaided ear. A “bat or ultrasonic detector” (UsD, in our case an Ultra Sound Advice S-25 detector) with a directional microphone (Mic) helps to localize such small cicadas even at distances up to 50 m.
SONGS OF EUROPEAN CICADAS
During last decades it became evident, that the song patterns of singing cicadas are very species specific and enable us to detect a presence of most species in a habitat without seeing and collecting them, just by recording and analyzing their acoustic emissions. In addition to this, one can recognize the hidden, morphologically inconspicuous species by analyzing and comparing their songs. As it is well known, in singing cicadas only males have characteristic sound producing organs – tymbals and are able to produce loud and species specific sound signals. Nevertheless, females of some species can answer to the courtship signals of males by short wing clicks. Similarly, males of some species use wing clicking as additional sound producing mechanism.
Phantastic songs of the S.E. Asian cicadas
The loud insect singers – cicadas – show in S.E.Asia very high diversity in forms, colours and acoustic signals. During the last few years I visited with my colleagues from Slovene Museum of Natural History in Ljubljana, Slovenia, a few times this region and recorded many fascinating songs of cicadas there. Here is just a humble digest of the rich acoustic soundscape, bound merely to the remaining but disappearing rainforests of the S.E. Asia
Represented digital recordings originate mainly from Thailand and Malaysia. More examples from Borneo (Sabah, Sarawak) one can find in the homepage of Klaus Riede, Germany.
BETWEEN BIOACOUSTICS AND MUSIC
There are many examples of animal sounds or vibration signals mentioned in this paper and presented in the form of oscillograms and sonograms. To get a better idea about these communication we present here the following examples of the animal sound and vibration signals.
Vibrational signals and songs are produced by many insects, among most interesting ones are produced by small bugs (Heteroptera) of the family Cydnidae. The signals are produced by two different mechanisms, a stridulation and by a body vibration or a simple tymbal mechanism. For their communication only the substrate vibration and not the airborne sound is crucial. More interesting are the vibrational songs during courtship and mating. Males produce first courtship song (MS-2) with repeated phrases composed by low frequency part followed by stridulatory chirps. After some time the male switches to the intense second courtship song (MS-3). If the female is receptive, it responses with prolonged high pitched stridulatory chirping (FS-2).
The predatory bug Phymata crassipes has many vibrational songs and one of them is used in alternation between males, females or even youngs. These bugs answer with such vibration signals also to various sounds and even to human speech or whistle and mimic the duration of such sound.One can listen to such alternation between a bug (Ph) and an experimentor (H)and see the sonagram below:
Even more surprizes awaits us in the acoustic world of the tropical and subtropical countries – where the endangered natural ecosystems still exist.
In contrast to European cicadas there some species sing like birds with high degreee of frequency modulation what sounds like this:
A number of singing cicadas is in many sites so high that they have to share time of singing with other species in a certain order to enable efficient communication. Therefore the sounds in the rainforest change from hour to hour as can be shown in the next examples from the Belum Forest, Malaysia.
More examples on songs of tropical cicadas can be heard in the homepage about Asian cicadas.