Results and discussion
Because of the wealth of new information observed in the high
frequency spectrum, the important question to answer is to
identify the nature of the observed spectral peaks. The recorded
signals do not depend on the insect’s condition alone; they also
vary for different parts of the insect. It is possible to identify signals
that are present only in live insects and thus come from internal
processes (Dokukin et al., 2010). These signals can originate either
from contraction of insect muscles or the hydrodynamic motion of
its internal fluids. While the exact identification of the nature of
each peak will be the subject of a series of separate works, here we
demonstrate several examples of such identification (not necessarily
unambiguous every time). This identification is made using
various physical, chemical, and biological stimuli.