Photos by Arlo Pelegrin                                                  



Photo thanks to Upper Delaware River Insects

Caddisfly life cycle includes 5 larva instars and one generation a year. They undergo periods of non-developmental growth in damp substrate during summer, when their habitat has dried up (McCafferty 1981).

When leaf detritus is at a minimum they resume development as a response to shorten day length in the late summer or fall, larval dormancy may be to ensure synchronized adult emergence (McCafferty 1981).

Pupation is almost always aquatic, transformation to the last larval instars to pupal stage happens in a sealed cocoon called the pupal case. The pupal case usually is some modification of the larval retreat (as described in a poem by Edna St. Vincent Millay in facts).

Pupal cases are generally attached to a fixed object. A larva will spend about 3 weeks in the pupal case for it to develop into an adult. At this time it will cut itself free and the adult will emerge and crawl out of water or swim to surface of the water (McCafferty 1981).

Photo by Scott Butner

During this time the Caddisfly is at its most vulnerable for fish predation. Adults generally fly way pretty quickly after they emerge from pupal case. They generally live to 1 or 2 months.

They are mostly nocturnal or crepuscular but many are diurnal. Mating generally takes place on the ground or on vegetation. It often starts with a swarming activity. The best time to mate is during wetter seasonal periods.

Females often lay masses of eggs in water by either dipping their abdomen in the water, diving in the water, or crawling into water.

Dew, fog, or rain liquefies the gelatinous material within which the eggs are laid allowing eggs or newly hatched larvae to drop or migrate into the water. The eggs of some species can remain dormant in dry periods. They then hatch and become larva and the cycle starts over.

Photo by Joshua Bergan

(All Facts from McCafferty 1981)