Chapter 1, The Reptilian Spectacle - UWSpace - University of ...

3.3.2 Gecko Spectacle Scale Transmittance
The spectacle scale transmittance spectra of geckos, in sharp contrast with that of snakes, shows near
100% transmittance throughout the visible and UV-A ranges with a drop in transmittance occurring in
the UV-B, but rising again in the UV-C with a characteristic peak at 254 nm before cutting off
completely at ~240 nm (Fig. 3-5).
% Transmittance
Transmission
100
75
50
25
Figure 3-5. Spectacle scale transmittance spectra in gekkonid geckos. Gecko spectacles exhibit
exceptionally high transmittance through the visible and UV spectra, close to or at 100% until dropping
somewhat in the UV-B, before peaking again at 254 nm in the UV-C.
3.3.3 Statistical Analyses of λ50%
The λ50% grouped by family are plotted in Figure 3-6 (next page). K-W test on ranks indicated a
significant difference between families (p < 0.0001). Individual comparisons between families indicate
that Colubridae exhibits significant differences in λ50% compared with Pythonidae and Viperidae. No
other significant difference was detected. These results are summarized in Table 3-3 (next page).
However, as can be observed in Fig. 3-6, not only are the mean λ50% of Elapidae considerably higher
than Pythonidae and Viperidae, but all λ50% are higher. A greater sample of elapids would be necessary
to statistically establish a conclusive difference.
Spectacle Scale Spectral
Transmission - Geckos
Phelsuma madagascariensis grandis
Gekko grossmanni
0
200 300 400 500 600 700
Wavelength (nm)
63