Why do shieldbugs smell of marzipan?
AThough they assume a heroic heraldic title in Britain, shieldbugs are often called stinkbugs elsewhere in the world because of their striking scents. Most British species use camouflage coloration to hide from predators, but should one be picked up in the beak of a bird, it will release a series of volatile, low-molecular-weight compounds from glands under its thorax. The resulting odour may be reminiscent of an oily almond, yet the taste is bitter and acrid, prompting the predator to release its catch.
The chemicals are harmless, but can result in staining. Handling the woundwort shieldbug at a wildlife event to demonstrate the smell to children left my palm coloured brown for days.