Monday, August 16, 2021

Lepidoptera scales are full of color and beautiful shapes

The scales determine the color of the wings and the body, which is why they are involved in the phenomena of cripsis, mimicry and aposematism.  The color of the scales comes from two mechanisms;  pigmentary color, given by the accumulation of pigments in the individuals' cavities;  and the structural color, which is produced by the diffraction of light in the microstructure of the scales, producing an iridescent color that changes according to the angle of observation.

  Some Lepidoptera have modified scale groupings, associated with exocrine glands, whose function is to disperse sex pheromones, thus contributing to the encounter of males and females.  These scales are located on the legs, wings and body folds, forming tufts or brushes that expand to spread the pheromone.

  From a taxonomic point of view, the shape of the scales is a relevant feature for the recognition of large groups of Lepidoptera.  For example, the moths of the superfamily Tineoidea have erect hair-like scales on the head, in Gelechioidea and Pyraloidea these scales are leaf-shaped and attached to the integument, while in Tortricoidea they have the same shape but are erect, which gives the head a rough appearance.

  Photo of a butterfly wing fragment through a microscope.

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