Still-water Caddisfly Life Cycle

If you are not familiar with the life-cycle of the Caddisfly, this photo series should give you a few fly tying ideas to go on. 

A typical caddisfly life-cycle.

Anabolia sp. (Limnephilidae) larva - one of the larger caddisfly larvae found in Alberta lakes.

A close-up of Anabolia with its cool color pattern. As the larva grows it simply
adds on to the front end of the case to make it bigger.

When ready to pupate, the larva seals off both ends of the case with a sieve-like plug made from silk extruded from glands near their mouth. This allow oxygenated water to circulate through the case as the transformation takes place.

A cut-away showing the pupa developing within the case. If oxygen levels drop too low, the pupa will undulate
(similar to cased chironomid larvae) to help circulate water through the case.

This pupa has almost completed its development. Note the well-developed legs, antennae, and wing-case all bunched together on the front half of the pupa.

When ready to emerge, the pupa cuts its way out of the case and makes its way to the surface to emerge. The trip to the surface can be a quick one - with the pupa buoyed by air trapped under the cuticle, undulations of the body, and sometimes a sculling swimming behavior using their hind legs.

Once at the surface, the cuticle of the pupa splits along the back and the adult caddisfly crawls out onto the surface. 

If you see lots of these on the surface you know that caddisflies have been or are emerging.

A typical adult caddisfly with its characteristic drab color and long antennae.

Caddisfly hatches are more common late in the evening but you will
sometimes see an emergence in the middle of the afternoon.

Mating takes place on shore-line vegetation with
egg laying taking place a short time later.