Hidden jewels

Jewel Beetles are highly coloured and probably the most collectable of the insects, after tropical butterflies. The colour in each case is not an inherent feature of the insect but results from the diffraction of light from the insect surface (a similar process to how rainbows are formed). In butterflies the diffracting surfaces are the scales on the wings. For Jewel Beetles and other highly coloured beetles, pictured left, the colour is due to light being diffracted by small ridges on the exoskeleton.

Whilst weeding the lawn I came across a Jewel Beetle-ish looking beetle coloured black and white, pictured right. Upon closer examination it did the typical Jewel Beetle behaviour when threatened of retracting the antennae and legs and dropping to the ground revealing jewel-like colours underneath (pictured below). It is a Callitris Jewel Beetle (Diadoxus erythrurus). (Callitris is a genus of coniferous tree native to Australia and New Caledonia).

The adult Jewel Beetle lives for a relatively short time (days to weeks). Most of the lifecycle is spent in the larval stage. The larvae in this case bore into Callitris trees favouring dying or dead branches on otherwise-healthy trees.

A wise insect the Callitris Jewel Beetle keeps its treasures well hidden.