ultrasonic chirps

I continued my research into ants and ultrasound last night and eventually discovered some papers on the subject.   It appears, after all, that some ants, at least, do make sound by using stridulation, although whether they do this to communicate with each other (for example as a distress call) or as some sort of echo-location system it is not known.  This would help to explain why my signal was made up of a repetition of the same note, each one being a separate ‘chirp’ component of the whole call.

Ultrasonic sounds are not uncommon in the insect world, or for that matter everyday recording.  Normally though they are simply part of the frequency range of an already audible signal, such as sibilance when people speak, or the call of a cricket.  What was most exciting about this find is that it could be a ‘hidden’ message totally out of the range of human hearing.

I have found some research by a Dr Hickling who recorded stridulation sounds of Black Fire Ants.  Although these are a different species, I do think there are similarities in the sounds.  I think mine is similar to the one he calls the ‘all is well’ signal.  Check out his recordings here.