J. Eur. Opt. Society-Rapid Publ. 22, 12( 2026) 119
Figure
5. Calliphora vicina’ s visual appearance is very intense for the visual systems of Calliphoridae species( blow flies), Parus caeruleus Eurasian blue tit, Zootoca vivipara lizard and Vespula vulgaris wasp, as shown here in terms of quantum catches. The reflectance peak located at 437 nm leads to high absorption by the SWS photoreceptors of all tetrachromatic vision species.
investigated blow flies’ cuticles for different organisms including C. vicina( Fig. 5) and L. richardsi( Fig. 6) blow flies themselves as well as some of their predators( i. e., P. caeruleus Eurasian blue tit, Z. vivipara lizard and V. vulgaris wasp) by calculating the quantum catches related to their photoreceptors. From this analysis, we cannot directly infer the species colour perception since it would require to take into account the light transmission through the organisms’ eye lenses and their neural processing of visual signals. In dipterans, for instance, visual sensitivity and colour discrimination vary widely among taxa and are often tuned to ecologically relevant cues such as host or mate detection [ 19 – 21, 57 ]. In addition, the visual background strongly affects detectability. In a specific background, a body colour that can be perceived may still remain undetected. For instance, camouflage strategies evolved in some species for millions of years involve mimetism through homomorphy and chromomorphy [ 73, 74 ]. Some observations can however be performed based on the calculated quantum catches. All selected species’ visual systems are highly sensitive to C. vicina and L. richardsi’ s visual appearances. C. vicina’ s colour is specifically intense for all the four species. Its reflectance peak at normal incidence and detection( located at 437 nm) gives rise to a high absorption by the SWS photoreceptors of all four investigated species with both trichromatic and tetrachromatic visions. This colouration appears very chromatic in the case of the common lizard, i. e., the quantum catches among the photoreceptor types differ the most, resulting in a highly saturated colour signal. With larger incidence and detection angles, these four species’ VSWS photoreceptors are more excited than their
SWS photoreceptors. These organisms have a vision well suited for this blow fly’ s blue colour since they have types of photoreceptors in this range, namely SWS and VSWS. L. richardsi’ svisualappearanceatnormalincidence and observation leads to a high absorption by the LWS photoreceptors of the Eurasian blue tit and the blow fly as well as by the MWS photoreceptors of the common lizard and the common wasp. This is due to its reflectance peak at 537 nm. If L. richardsi seems to be very chromatic for all four species, the common lizard is the species having the most chromatic sensation of this visual appearance. With higher incidence and detection angles, the photoreceptors absorbing the most reflected light also change: down to the SWS photoreceptors in the cases of the Eurasian blue tit, the common lizard and the common wasp and down to the MWS photoreceptors in the case of the blow fly.
The optical responses of the investigated blow flies’ photonic structures were simulated as perfect photonic crystal models( Fig. 7) using the geometrical parameters measured from the electron microscopy observations( Fig. 2) in order to assess whether the measured reflectance spectra arise from the structures observed by SEM and TEM. In the case of L. richardsi, only the top multilayer was found to have dimensions that could be responsible for the optical behaviour of the cuticle. The thicknesses of the layers composing the bottom multilayer are too large for giving rise to an optical photonic bandgap in the range of interest. The middle multilayer could give rise to a predicted reflectance peak in the near UV range. However such a peak is not measured by spectrophotometry. This might be explained by a lack of refractive index contrast between both kinds of layer.