Left–right asymmetry in the microstructure of the hindwings of European hornet revealed by scanning electron microscopy and microscopic vibrational circular dichroism

Observation of hornet hindwings using scanning electron microscopy revealed a coating composed of helically wound hairs of approximately 10 μm in diameter and 100 μm in length. A strict enantiomeric relationship in the organ morphology existed in the area closest to the leading edge of the wings: the hairs on the right wing exhibited left-handedness, whereas those on the left wing exhibited right-handedness. Evaluation of microscopic vibration circular dichroism spectra indicated that both sides of the wings comprised β-sheets. However, a notable difference in VCD spectral shapes existed between the left and right wings (VCD_left and VCD_right, respectively), although their IR spectra were nearly identical. From the spectral shape of the difference (VCD_left - VCD_right), one possibility is proposed that the handedness in the hairs on the left and right hindwings is related to the opposite chirality of the protein structure. The correlation between organ-level enantiomeric relationships and the protein secondary structure observed here is a novel observation that requires further investigation to obtain deeper insights.