Towards nano-physiology of insects with atomic force microscopy

Little study of insects with modern nanotechnology tools has been done so far. Here we use one of such tool, atomic force microscopy (AFM) to study surface oscillations of the ladybird beetles (Hippodamia convergens) measured in different parts of the insect at picometer level. This allows us to record a much broader spectral range of possible surface vibrations (up to several kHz) than the previously studied oscillations due to breathing, heartbeat cycles, coelopulses, etc. (up to 5–10 Hz). Here we demonstrate three different ways with which one can identify the origins of the observed peaks – by physical positioning the probe near a specific organ, and by using biological or chemical stimuli. We report on identification of high frequency peaks associated with H. convergens heart, spiracular closer muscles, and oscillations associated with muscles activated while drinking. The method, being a relatively non-invasive technique providing a new type of information, may be useful in developing “nanophysiology” of insects.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideResearch highlights▶ Described AFM method allows detection of internal surface oscillations of insects up to 0.001 nm and in a spectral range from 0.01 Hz to several kHz. ▶ 0.5–0.6 Hz and 293 Hz spectral peak are associated with heart activity of Hippodamia convergens. ▶ 133 Hz and a weaker peak of 350 Hz are presumably associated with the action of the spiracular closer muscles. ▶ Spectral behavior of H. convergens while drinking is studied.