Scarabaeidae  

Scarabaeidae (Scarab Beetles)
This a large family of beetles, ranging in size from small to very large. They are usually black with a heavy carapace, and powerfully built. Many of these beetles display little interest in flowers, preferring to roam across the ground and hunt for other insect prey. Some of them are attracted to dung, which is shaped into a ball and rolled along the ground. This is deposited in a suitable hole, where the eggs are laid. Only one subfamily will be described, because the Scarab beetles in this group are more likely to visit flowers. Cetonniae (Flower Scarab Beetles): These are medium-sized beetles, somewhat round and flattened in shape. They are variably colored, sometimes iridescent green, black, or with brown and yellow patterns. The antennae are short and stout, like other Scarab beetles. The adults often appear on flowers, feeding on pollen, if not the flowers themselves. The larvae feed on plant roots, rotting wood, and decaying organic material in the ground.

Scarabaeidae (scarabs) is prey of:
Solpugidae
Scorpiones
Araneae
Typhlosaurus
Aves

Based on studies in:
Namibia, Namib Desert (Desert or dune)

This list may not be complete but is based on published studies.

Chitin layers produce gold and silver colors: jewel scarab
 

The forewings of jewel scarabs produce gold and silver by having 70 layers of chitin that become progressively thinner with depth resulting in different refractive indices.

 
  "A team of researchers at the University of Costa Rica has found that the  beetles' metallic appearance is created by the unique structural  arrangements of many dozens of layers of exo-skeletal chitin in the  elytron, a hardened forewing that protects the delicate hindwings that  are folded underneath... In these beetles, the cuticle, which is just 10 millionths of a meter   deep, has some 70 separate layers of chitin—a nitrogen-containing  complex sugar that creates the hard outer skeletons of insects, crabs,  shrimps, and lobsters. The chitin layers become progressively thinner  with depth, forming a so-called 'chirped' structure. 'Because the  layers have different refractive indices,' Vargas says, 'light  propagates through them at different speeds. The light is refracted  through—and reflected by—each interface giving, in particular, phase  differences in the emerging reflected rays. For several wavelengths in  the visible range, there are many reflected rays whose phase  differences allow for constructive interference. This leads to the  metallic appearance of the beetles.' This is similar to the way in which a prism breaks white light into the   colors of the rainbow by refraction, but in the case of these beetles,   different wavelengths, or colors of light are reflected back more  strongly by different layers of chitin. This creates the initial palette  of colors that enable the beetles to produce their distinctive hues." (Stark 2011:1)

  Learn more about this functional adaptation.