Life Cycle

The life of a Glossosoma intermedium begins in the form of an egg.  The egg begins at the bottom of a moderate flowing stream along its rocky surface.  Around May, the eggs starts to hatch and from them come the larvae (Wallace 2011).  The larvae would then build itself a case as a mean of protection from predators such as fish.  Depending on the situation the larvae may leave its case and drift to find a habitat where food sources are more abundant.  The larvae has five instars stages (Cavanaugh, Haro and Jones 2004).  In each it will become bigger through molting.  After each time it molts it will have to build itself a new case (Cavanaugh, Haro and Jones 2004). Once the larvae is ready to reach adulthood it would leave its case and swim ashore or climb onto an emergent rock (Wallace2011).  From there the skin of the larvae would split open.  The adult would then emerge and fly away. 

When laying the eggs, the adult female caddisfly would dive into the stream attaching itself to the bottom of the stream (Wallace 2011).  It would then lay eggs in groups.  After laying the eggs it would then leg go of the rocks that it was holding onto and float to the surface.  Upon reaching the surface it would then fly away.



Glossosoma intermedium are bivoltine (Cavanaugh, Haro and Jones 2004). They produce two groups of offspring in a year, one in summer and one in winter.  The summer one range from May to November and the winter range from November to April (Cavanaugh, Haro and Jones 2004).

Graph showing the distribution of adults Glossosoma intermedium collected throughout the year


        Theblue bar represent the adults collected in a specific date range
           The red bar represent adults collected in a specific date range however those obtain at the same location    and date are counted as one