The broader picture: Insect glamour

THESE dazzling little water-borne creatures are the most expensive insects in the world. They wallow around their tanks, weighed down by their riches, looking like some- thing from Tutankhamen's tomb. But they are actually examples of the humble caddis worm (or caseworm), the larva of the caddis fly. The insects - which are less than a centimetre long - are famous for warding off predators by means of a protective case which they weave around themselves using stones, shell, bits of wood or leaf, or whatever else happens to be lying around. The larvae can be found in ponds and rivers all over the world, and in quartz-rich areas have sometimes been found coated with crystals.

The French artist and naturalist Hubert Duprat has been a fan of the caddis worm for many years. When he learned that scientists had discovered them covered in gold and stones at the bottom of a river in South America, it set him thinking. He collected some larvae, and gently removed their cases. Then he lowered them, naked, into an aquarium in which he had made piles of gold flakes, rubies, opals, mother-of-pearl and lapis lazuli. For a few days, the larvae crawled about nude and disorientated, but then their natural modesty took over and they began to use their hook-ended legs to grasp the gold and gems, and bind them into a casing by releasing a sticky silk. In nature, caddis worms arrange their materials with a fashion designer's precision, and, as can be seen from the pictures, they did the same in Duprat's aquarium. One made itself an elegant collar of narrow gold strips. Another busied itself wrapping two bands of pearls about its abdomen. A third created a lapis belt.

Duprat has been exhibiting his insects, dripping with gold like Manhattan socialites, in their aquariums in several galleries, including the Cartier Foundation in Paris. While the larvae metamorphose, their cladding becomes a cocoon. Then, once the occupants have moved on, Duprat puts the empty cocoons on display (far right) and sells them to collectors, who treat them as natural works of art or turn them into pendants. The jewel-cocoons change hands for about pounds 2,000.