About the Caddisfly
Order Trichoptera, Family Limnephilidae
The Caddisfly also goes by the name Sedge.
What does the Caddisfly look
like? An adult Caddisfly is a water moth. The adult looks much like a moth, but the wings are smoother and sometimes partly see-through. Most Caddisflies in British Columbia are about two centimeters, but many are half that size, and some are twice that size.
Caddisfly larva look like a grub (a short, fat, creamy white worm-like creature) with a dark head, and are mostly hidden in protective casings on the lake bottom. The casing is made of small rocks, tiny twigs and bits of leaves and other bottom debris. They crawl slowly around, hauling their casing with them.
Caddisfly pupa look much like the adult, just with underdeveloped wings. Sometimes they are a very bright green colour.
Did You Know… Sedges are the third most important food source for trout in the BC interior, after midges and Scuds
Where does the Caddisfly live?
Sedges have a wide range of watery habitats, but they are most common in shallow, cool and well-oxygenated lakes throughout British Columbia. Many species of Caddisfly are found around the world.
What is the life cycle of the Caddisfly?
The Caddisflies start hatching after all the other major aquatic insects, and they are the first to disappear in the fall. Click here to see the life cycle of a caddisfly. They mate on the lakeshore, and then the female runs over the lake surface (not actually flying) dropping bright green eggs. The eggs sink and then hatch into larva. When the larva are born, they build tiny, cone-shaped casings and start growing, rebuilding the casing about five times. Finally they seal it and pupate. The pupa then breaks the casing, swims to the surface and hatches into an adult Caddisfly, usually in late May. The pupa swims up quickly (by pupa standards, of course - they are not olympic swimmers!) Once it reaches the surface the caddisfly changes into an adult and flies away quite rapidly. When a caddis hatch is happening, fish must be aggressive to catch the adults before they fly away. You can spot the pupal skins of caddisflies floating on the surface of lakes at that time. The adults live up to two months. This cycle repeats itself once or twice per year.
Food for Thought ... Fish often swat at the caddis adult and drown it before it comes back to eat it. Why do you think that the fish does this rather than just gulping it down right away?
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