‘‘Physical’’ approach to identifying of the spectral peaks by locating the AFM
probe near the heart (curve 2). Control curve (3) corresponds to dead insects. Curve
(1) is the spectrum collected from the elytra, near the pronotum. Spectra are shifted
for better visual comparison as follows: 50 nm is added to low frequency curve 1,
+0.01 nm to curve 1 and +0.005 nm to curve 2 of high frequency part. Only parts of
spectra showing differences are shown.