Not all apparently gynandromorphic butterflies are gynandrous: The case of Polyommatus icarus and its relatives (Lepidoptera: Lycaenidae).

Beside the more than two thousand normal specimens of Polyommatus icarus (Rottemburg, 1775) yielded by rearing experiments, there was one perfectly bilateral dichromatic individual first considered to be gynandrous. On the basis of analysing genitalia traits, wing surface covering scale micromorphology, and the spectral characteristics of the blue colour generated by the cover scales, the gender of the specimen has been identified as female. This exemplar was investigated in comparison with gynandrous specimens from the collections of the Hungarian Natural History Museum exhibiting various degrees of intermixing of blue and brown coloration. Focus stacking microscopy for detailed scale morphology and UV-visible reflectance spectroscopy was used for the characterization of the optical properties. Inspecting literature references and the Lycaenidae collection of the museum, further examples have been found for female bilateral dichromatism in the closely related polyommatine lycaenid species Lysandra bellargus (Rottemburg, 1775) and Lysandra coridon (Poda, 1761) what suggests that polyommatine female dichromaticity may be displayed by the manner of bilaterality and mosaicism, phenomena hitherto solely connected to gynandromorphy.

High accuracy of color-generating nanoarchitectures is kept in lowland and mountainous populations of Polyommatus dorylas (Lepidoptera: Lycaenidae: Polyommatinae).

It is known that the size of the scales covering the surface of the Lepidoptera wings is in correlation with body size: larger species possess larger scales. However, butterfly individuals representing the various generations of the same species but differing in body size were not investigated in this respect. Similarly, the question whether different scale size may influence structural color generation based on nanoarchitectures in the scale lumen was never addressed. Populations of lowland (environment of Budapest, Hungary) and upland (Carpathian Mountains, Romania) Polyommatus dorylas were compared in terms of voltinism, wing and scale size, and the structural origin of blue coloration. Data analysis showed that the univoltine upland population exhibits a larger wing and scale size. On the other hand, the nanomorphology of the blue color-generating scales was identical when compared between univoltine and bivoltine populations. Coloration was also identical when measured with a spectrophotometer under ultraviolet and visible light. This high accuracy present in the male structural coloration suggests that it is controlled genetically. Body size alteration for enhanced thermal fitness has no influence on the fine structure of the nanoarchitecture present in the scale lumen.