The ears under the water level : tympani are blocked and sounds transits through bone conduction. There, the audition is much less sensitive than in the air. So I was trying to catch sounds from water bugs, I began to use home-made hydrophone. It's much better than spending too much time the head in ponds...
My first experiments were done using a single piezoceramic disc. And that was disappointing...
Later, I found a very strange component, that I still can't identify. This small metal cylinder was used in a broken throat microphone. I just put a layer of glue around it, then connect into a minidisc microphone input, with plug-in power.
I tried it in La Loire in Tours, Fr (05.05.2005). At noon, Sigara dorsalis was singing near the riverbank.
The same day, in the same place, I also made some test with a modified stethoscope that I used for a composition (Sanguine, published by Eetapes in The Wall Are Whispering III). I put an electret microphone inside to record my bone articulations and blood pressure. I used some glue to make it waterproof then throw it into the river.
The result is still a Sigara dorsalis song, but here is also a drone caused by the sounds of the road nearby coming in the resonance chamber made by the stethoscope. If you listen carefully, you'll even recognise crows flyer over...
The next step was to buy a cheap hydrophone. The one I proudly own is Aquarian H2a-XLR .
The following sounds were recorded in Lac de Beuil, Valberg, France (about 1700 meter high, 03.08.2007). Since the sounds of these waterbugs was very low in term of intensity, the self-noise of the microphone was still annoying so I used some noise-reduction on this recording. This is why there are quite a lot of (reverb-type) artefacts. I have absolutly no idea about what species make these sounds. If you have any clue...
Another recording ! This time (9th December 2008), it was in Taiwan, Chiayi county. Coming from this pond, I noticed a very tiny sound. When I looked very close to the mud, I could see small black dots swimming. It reminded me the insects found in Laaksare, Estonia (check this page for a recording above the water). I didn't had my Aquarian hydrophones with me but only a home-made pair built with two piezoceramic transducers covered with thermoplastic (don't know the correct English name, in French "gaine thermo-retractile"). So I threw them in the water, connected to a portable recorder (Sony PCM-D50). Surprisingly the sound was quite loud. Eventually some insect began to eat my hydrophone, but ok, it was harmless... Pictures below are the situation with special listening guest, my collaborator and guide in this region, Hsu Yen-Ting.
For continuing the exploration of the sound world of waterbugs, I recommend listening :
