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

Abstract

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.

Keywords: Nanoarchitecture; Polyommatina; Sexual signal; Spectral properties; Voltinism; Wing scale size.