October caddisfly

Judy Li

Latin name: Dicosmoecus gilvipes

Larvae of October caddisflies are common algae-grazers on boulders and bedrock. Their rocky cases protect them from fish predation, but they are important food for birds. In Oregon, harlequin ducks migrate inland to nest and depend on these caddis to rear their young. During our 1996 study, harlequins were forced to return to the ocean when flooding at Quartzville Creek removed this species, illustrating their importance as links between stream and riparian systems.

Did you know? The October Caddisfly is one of our largest caddisflies, and recognized by fishermen to be important prey for salmonids in the fall. Our studies illustrated they're important to birds as well.


For harlequin work: Wright, K.K., H. Bruner, J. Li, R. Jarvis & S. Dowlan.  2000. The distribution, phenology and prey of harlequin ducks, Histrionicus histrionicus, in a Cascade mountain stream, Oregon. Canadian Field Naturalist 114:187-195.

In the John Day: Li, H. W., G. A. Lamberti, T. N. Pearsons, C. K. Tait, and J. L. Li.  1994. Cumulative effects of riparian disturbance in small streams of the John Day Basin, Oregon. Transactions of the American Fisheries Society 123(4)627-640.; Tait, C.K,, J. L. Li, G. A. Lamberti, T. N. Pearsons, and H. W. Li.  1994. Relationships between riparian cover and the community structure of high desert streams. Journal of the North American Benthological Society 13: 45-56