Fig. 1

Dorsofrontal and ventrolateral parts of L. macaronius eyes possess different corneal nanocoatings, resulting in different light reflectance properties. a Light microscopy (lateral view) of a L. macaronius head. The furrow dividing the ventrolateral (VL) from the dorsofrontal (DF) parts can be seen. b Photograph of an owlfly (photo kindly provided by T. B. Bersatu from http://www.thebugmaniac.com). c and d Representative AFM scans of corneal surfaces of the DF (c) and VL (d) eyes reveal clear difference between the nanostructural coatings of the two eye parts. The surface height (in nm) is indicated by the color scale shown next to the images; the minimum level is set to zero for both scans. Both squares are 4 × 4 μm and in the same height color scale. e Cross-sectional profiles of DF (in orange) and VL (in brown) cornea of 1 µm length. The location of the cross-sectioned zones is indicated by the white bars on the AFM scans above. f and g Measurements of the broadness (f) and the height (g) of protrusions from the DF (orange) and VL (brown) eye parts. Data are shown as mean ± SD, n = 20. Student’s t test was used to assess statistical significance, “ns” stands for non-significant, “****” indicates the p value ≤ 0.0001. h Ratio of the reflection spectra (from 250 to 750 nm) measured for the DF and VL eye parts. Data are shown as mean (in red) ± SD (in orange), n = 2. The spotted line shows the ratio of 1.0 (no reflection difference) across the spectrum