"What's that... huh.. thing?" is probably the first thing many people would say looking at the picture above, and the second of course would be: "Is that real?".
Yes it's real and it's not a spider under one of those diet/energy-giving bars made of muesli, seeds and fruits. Infact this picture has been shot underwater and the protagonist is just an amazing insect called caddisfly, and its case.
Maybe, you can better understand it, looking at the ventral side of another caddisfly:

caddisfly
©Bedwetting in Australia via Flickr

If you have never heard about caddisflies, don't worry, I'm just going to explain you:

THE CADDISFLIES

Caddisflies ( image on the left © 1997 David Funk ), also known as sedge-flies or rail flies (Order Trichoptera, from Greek trich, "hair", and ptera, "wings") are small moth-like insects having two pairs of hairy membranous wings. They are closely related to Lepidoptera (moths and butterflies) and the two orders together form the superorder Amphiesmenoptera. Caddisflies have aquatic larvae and are found in a wide variety of habitats such as streams, rivers, lakes, ponds, spring seeps, and temporary waters (vernal pools). The larvae of many species make protective cases of silk decorated with gravel, sand, twigs or other debris. What you've seen in the first two pictures are just these protective cases (and in the first picture I've to say that the pink pebble near the head of the caddisfly really seems like a fancy cute hat...!)

The adult stage
As I've said before, in their adult stage, they are just like little moths, usually quite featureless and banal but sometimes more colourful and garish (without reaching the beautiful levels of butterflies and moths)

caddisfly
©Glenn Firebaugh

caddisfly
©macrodomo via Flickr

caddisfly
©Tauromardo via Flickr

The larval stage
By the way what make them really amazing is their larval stage:
Caddisflies are considered underwater architects because most species use silt for building throughout their larval life according to three behavioral groups based on this use of silt: retreat-making caddisflies, case-making caddisflies, and free-living caddisflies. Those that build retreats build a net or retreat from silt and other materials and use it to catch food items such as algae, aquatic invertebrates and zooplankton from the flowing stream. Case-making caddisflies make portable cases using silk along with substrate materials such as small fragments of rock, sand, small pieces of twig, aquatic plants, or sometimes silk alone. Many use the retreats or cases throughout their larval life, adding to, or enlarging them as they grow. Free-living caddisflies do not build retreats or carry portable cases until they are ready to pupate.

The most interesting are for sure the case-making caddisflies. Using for their cases what they find in their own habitat, they could reach a good level of camouflage:

caddisfly

Usually cases go from "niggling" to "quite disgusting" looking like excrements of bigger animals:

caddisfly
©Frank Greenaway/Dorling Kindersley

By the way what made them so special is that being made with what the larvae find on their way they sometimes could be quite unusual like this one made just with pieces of leaves:

caddisfly
Copyright © 2006 Donna Hollinger

Some caddisflies instead build their cases using just their own silk looking like these:

caddisfly
© 1997 James C. Hodges, Jr.

Caddisflies can often be found in very numerous colonies:

caddisfly
© Jason Neuswanger www.troutnut.com

Finally, if you are fishermen, you probably know that caddisflies imitations are used in Fly Fishing to catch trouts and other species. Imitations have reached amazing levels of realism:

caddisfly
©Graham Owen


THE ARTIST THAT CONVERTED CADDISFLIES INTO JEWEL CREATORS

caddisfly
caddisfly
Photos Jean-Luc Fournier. Courtesy Art:concept, Paris, and Zero Gallery, Milan.

Now that we know what caddisflies are and what they are able to do., I want to tell you about the crazy idea of an artist called Hubert Duprat that having thought that being able to control what kind of materials larvae would get in contact with, then you woud also be able to control somehow the final look of the case. So he had the outlandish idea of converting caddisflies larvae in authentic jewelry creators!
Having been in the past a naturalist he knew that the larvae are remarkably adaptable: if other suitable materials are introduced into their environment, they will often incorporate those as well. So in the early eighties he started to collect the larvae from their normal environments and took them to his studio. There he gently removed their own natural cases and put them in tanks filled with his own materials, from which they began to build their new protective sheaths. When he began the project, he only provided the caddis larvae with gold flakes. Since then, the larvae have enjoyed various semi-precious and precious stones, including turquoise, coral and lapis lazuli, as well as sapphires, pearls, rubies, and diamonds:

caddisfly
caddisfly
caddisfly
Photos Jean-Luc Fournier. Courtesy Art:concept, Paris, and Zero Gallery, Milan.

Is the precious case the work of the insect or the work of the artist? Did the caddis larva owe nothing to the artist (who is simply the author of one noise among the thousands of other noises in its environment) or is the caddis worm merely the executor of the artist’s project?
What it's sure is that whatever you think about Durat's idea this is the only known case of animals creating luxury objects for men and even if it seems quite odd it has really amazed me.

caddisfly
caddisfly
caddisfly
Photos Jean-Luc Fournier. Courtesy Art:concept, Paris, and Zero Gallery, Milan.

In this video you can even see Durat caddisflies on the job:




Further reading:


Nature
  1. Trichoptera Tree of life web project page about caddisflies. You can find a lot of scientific and naturalistic info about Caddisflies
  2. Catalog of Aquatic Macroinvertebrates Battle Ground School District webpage. You can find many pictures of caddisflies larval stage
  3. Caddisflies DK Images gallery. A rich gallery of Caddisflies images
  4. Caddisflies by Karen Blankenship Exhaustive page about Caddisflies
  5. Insect Order Trichoptera Troutnut.com (Website about Fly Fishing for trout) article. Info and underwater pictures about trichoptera
Art
  1. Trichopterae Cabinet (Quarterly Magazine of Art & Culture) article about Hubert Duprat's "Larva Art". You can find info about Duprat's work
  2. The Wonderful Caddis Worm: Sculptural Work in Collaboration with Trichoptera Leonardo (Journal of the International Society for the Arts, Sciences and Technology) article. A conversation between the artist Hubert Duprat and art critic Christian Besson.