Fig. 5
From: Comparative and functional analysis of the digital mucus glands and secretions of tree frogs
SFG spectra of frog mucus. a Comparison of ventral digital (crosses) and abdominal (circles) mucus in Hyla cinerea in (a) PPP and (c) SSP polarisations. CH3 vibrations include methyl symmetric, methyl Fermi, and methyl asymmetric vibrations. b Comparison of the ventral abdominal mucuses of the arboreal frog species H. cinerea (black) and Osteopilus septentrionalis (red) as well as the terrestrial species Pyxicephalus adspersus (blue) and Ceratophrys cranwelli (magenta) in (b) PPP and (d) SSP polarisations. The solid lines represent the fitting curves using the Lorentzian equation (Eq. 2). The spectra are offset along the ordinate axis in steps of 100 (PPP) and 50 (SSP) for clarity