Building a house* (like a caddisfly)

Adult caddisfly - Macrostemum zabratum
Credit: Insectarium de Montréal (André Sarrazin)
Adult caddisfly - Macrostemum zabratum
  • Adult caddisfly - Macrostemum zabratum
  • Caddisfly larva in its case - Psilotreta labida
  • Children having fun with a caddisfly puppet on the “Nature is your Shelter” immersive pathway
  • Children having fun on the “Nature is your Shelter” immersive pathway
  • Children having fun on the “Nature is your Shelter” immersive pathway
Building a house* (like a caddisfly)

Building a house like a caddisfly takes a lot more than a stack of wood! Because however discreetly the larva of this insect goes about its business, the sophisticated manufacture of its shelter has what it takes to impress the best and brightest builders of this world. Let me tell you about the caddisfly…

Adapted to life in fresh water, the larva surveys the bottom of our ponds, lakes and rivers in search of plants or small invertebrates to feed on. Frequent moving about, required by its search for food, makes it vulnerable… But never mind: fine architects that they are, certain caddisfly species have developed portable shelters in the form of individual protective cases.

Architect, engineer, weaver…

Construction of the cases calls for advanced engineering techniques that result in buoyancy, resistance, and adhesion in an aquatic environment. The larva constructs its shelter based on different resources harvested underwater, such as twigs, pebbles or mollusk shells. “Close-knit,” these materials are welded together by a silk that the larva spins.

That silk is made up of fibers that are particularly effective for gluing objects underwater. Its physiochemical properties and the structure of the glands that produce it ensure that it operates like double-sided adhesive tape. Incidentally, that fiber is being studied in the biomedical field, notably with regard to gluing together damp tissue, like bones.

On the fly

At the end of their larval stage, caddisflies abandon their cases and weave themselves a cocoon, inside which they turn into pupae, then into adults. It’s during this last stage that they break away from aquatic life. They then benefit from adaptations associated with flight to take off in search of a partner. Similar to certain moths, the adult caddisfly is distinguished by wings covered with a fine layer of down and positioned at an angle like the roof of houses, above the abdomen.

Sensitive to various pollutants, the different caddisfly species are good indicators of the health of a body of water. Furthermore, they’ve mastered the art of constructing environmentally-friendly homes by making the most of the resources immediately available to them. An inspiration for building the world better and for better dwelling in it.

Finally, building a house as in the song by Félix Leclerc requires “a bricklayer, a contractor, one or two good carpenters, a plasterer and a painter…” – or more simply, a single caddisfly!


The title comes from a song of that name (“Pour bâtir une maison”) by Félix Leclerc

Feel like learning more about animals’ shelters?

Nature is your Shelter
This year, experts from the Biodôme and the Insectarium are offering an immersive and fun pathway on this theme, at the Jardin botanique.

Until September 3, 2018

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