Amina Thaj and Sheeba S
Background: Butterfly wings are covered by tiny, coloured plate like setae called scales. Zizula hylax the ‘tiny grass blue’ is a small sized butterfly which belongs to the ‘Lycaenids’ or blues family. It is characterised by the dull violet blue appearance on the dorsal wing area and, they are pale grey with multiple arcs of brown dashes, brown border termen surrounded by numerous cilia on their ventral wing area.
Objective: To investigate the wing scale morphology and length & width of scales using micrometry.
Methods: ‘Zizula hylax’ is collected using handheld insect net in which they are pinned into the insect box. The method of Grodnitsky and Kozlov (1991)  was followed. The scales were scrapped off from distinct regions of dorsal and ventral wing separately which is taken in different glass slides. The sample is fixed with xylene when evaporates is studied under light microscope. Photographs were taken to record the images which is viewed under the light microscope. Micrometry is used to measure the length and width of the scales.
Results: A total of 151 wing scales were analysed. 62 varieties of scales were studied from the dorsal blue coloured wing area and 89 varieties of scales were studied from the ventral ash coloured wing area. A typical scale consists of an abwing or upper lamina which constitute the upper portion of scale, an adwing or lower lamina which constitute the lower portion of the scale and a stalk. Several transverse lines run on the surface of the scales. Study on dorsal wing scales shows several dull black, pale yellow and dull brown coloured scales with flat and short size. Denudations of the scales are not well defined. The structural scales form the blue colour on the dorsal surface. The blue colour is formed when the light passes through the pale black, brown and yellow scales present in this region. The dimensions of the wing scales ranges between 74.86µ-94.56µ in length and 55.16µ-74.86µ in thickness. The ventral wing scales shows several long- narrow scales unlike the dorsal side. The ventral side of the ‘Zizula hylax’ is ash coloured and 89 scales were identified. All are transparent and glassy type white scales. Some flat white scales have also been seen. Here, the denudations are not yet clearly defined. The transverse lines can be seen clearly. The dimensions of the scale’s ranges between 82.74µ-177.3µ in length and 55.16µ-74.86µ in thickness.
Conclusion: The present study provides an idea about the different types of scales, their morphology and size mainly the length and width. Scales play an important role in the life of butterfly as it aids in flight, predator defence, thermoregulation, camouflage, mimicry, and coloration. Studies on wing scales possess many bioinspired applications also.
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