Identifying and Classifying Butterfly Type and Wing Pattern

Butterflies are admired for their beauty and vibrant color patterns. Biologists are keen on measuring the reflectance of butterfly wings in the visible and ultraviolet (UV) ranges to better appreciate the species and its relations with its ecosystem.

Avantes systems can be used efficiently for measuring these types of delicate biological samples. Recently, Avantes conducted some testing with a few customer-provided samples and the results were very impressive.

Equipment and Setup

To perform the reflection measurement, an Avantes AvaSpec-2048L spectrometer was used along with a 400 µm core UVIR broadband reflection probe and Avantes high power AvaLight-XE light source. A WS-2 diffuse white reference tile, which was the reference for the measurement, was placed in a fixed position on the Thin Film Stage and used as the surface on which the sample was positioned. Below are some images of the sample arrangement and samples.

Reflection measurement

Sample 1

Sample 2

Procedure

The reference tile was kept in a fixed position as a butterfly’s wing was measured at several locations. The choice of locations were those which revealed clear differentiation from other areas of the wing. A dark and reference was chosen with the WS2 white reference tile, then the percent reflectance was measured on the samples.

Observations

There were remarkably varying differences between the measurement spots across the wings of the butterfly. Locations 1-4 are illustrated in Figure 1 and locations 1-2 relate to Figure 2. Figure 1 reveals spectral features (peaks) in the visible and UV while Figure 2, which measures a much darker sample, has fewer prominent features and significantly lower reflectance values.

Figure 1

Figure 2

Taking the Lab into the Field

To simplify field measurements of this type, Avantes provides portable carrying cases for the spectrometer, fiber optics and light source. The AvaSpec instruments and light sources can be powered in the field via Avantes line of battery packs or with relation to the spectrometer via laptop USB connection. The AFH-Ocular is a unique accessory for containing a small tipped (1.5 mm diameter) fiber optic probe (refer image below) which enables visualizing the measurement area for a measurement during the actual measurement.

This information has been sourced, reviewed and adapted from materials provided by Avantes BV.

For more information on this source, please visit Avantes BV.