WONDERFUL WORMS

Polychaetes are among the most diverse of all marine organisms.

Most polychaete worms are covered in hair-like bristles, so they also go by the name of bristle worms. They usually have well-developed jaws and each body segment has a pair of limb-like muscular protrusions. These ‘limbs’ can be used to crawl and burrow. In some species, such as green paddle worms, they have become flflattened into little oars, enabling the worms to actively swim around. With over 10,000 species of polychaete known, including the fearsome bobbit worms of BBC’s Blue Planet II, it’s a body plan that works well.

Light show

The purpose of these colours has long been debated, but recent investigations into the nano-structure of the bristles and hairs have revealed the first known instance of natural photonic engineering. Under an electron microscope, each filament is shown to be a hollow tube whose walls in turn comprise some 88 layers of