Data from: Structural colours in diverse Mesozoic insects
Data files
Aug 03, 2020 version files 7.22 MB
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SI_File_01_Cai_.docx
Abstract
Methods
For standard observation, fossils were polished using different grades of sandpaper and diatomite powder, to get as close to the inclusions as possible without damaging them. Where it aided observation, some pieces were polished into very thin slices, making the insect inclusions clearly observable and the surrounding amber matrix almost transparent in bright light. Photographs against various backgrounds were taken using a Canon EOS 5D Mark III digital camera, equipped with a Canon MP-E 65 mm macro lens (F2.8, 1–5X), and with an attached Canon MT-24EX twin flash. Focus stacking software (Zerene Stacker, Version 1.04) was used to increase the depth of field. The resultant images were edited in Photoshop only to correct brightness and contrast. Two amber-entombed wasps (metallic coloured and silvery) were selected for ultrastructural analysis of the cuticles. Ultrathin (70 nm thick) sections were cut with a Diatome 3 mm 45° diamond knife, mounted on formvar-coated copper grids, and air dried. Unstained sections were imaged using a JEM-2100 Plus transmission electron microscope (at Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences) at 80 keV. The sectioned samples were mounted on stubs with double-sided carbon tape. The sectioned surface was imaged with a LEO 1530 VP analytical scanning electron microscope controlled by JEOL InTouchScope version 1.05A software, using the variable-pressure secondary electron detector at low vacuum and at 18 keV.