May 4 Speaker- Steve Moulton on Caddis

Dr. Steve Moulton, NVATU Chapter Member, will deliver a presentation of interest to fly fishers and conservationists featuring information about the distribution, diversity, biology, and ecology of caddisflies. He has conducted research on the biogeography, taxonomy, and ecology of caddisflies throughout North America, with special emphasis on the faunas in the Ozark/Ouachita mountains and southwestern United States.

Caddisflies are one of the most important insect groups known to flyfishers. There are approximately 1700 species of caddisflies in North America with the World fauna variously estimated between 10 and 50 thousand species; over 300 species have been documented from Virginia. Caddisflies play an extremely important role in aquatic ecosystems by processing organic material and serving as a food base for other animals. They occur in springs, streams, rivers, ponds, and lakes through the world; a few species are predominantly terrestrial throughout their entire life cycle and one group inhabits marine waters. Despite occupying a wide range of habitats, Caddisflies are generally intolerant of poor water quality and stressed environmental conditions. As such they are often used by water resource management agencies as indicators of the aquatic health.

Caddisflies undergo complete metamorphosis that includes a larva, pupa, and adult; each of these stages are modeled as flies. These stages range in size from approximately 2mm (No. 24 or 26 size hook) to over 40 mm (No. 4 or 6-size hook). Larvae are soft-bodied and usually cream-colored or greenish with the head and thorax (segment of body possessing the legs) variously colored from tan to dark brown or black. Depending on geography and habitat, caddisfly adults will emerge year-round. Some groups (e.g. grannoms) are highly synchronous in their development and ultimately emerge in large swarms for a one or two week period. Most other species have asynchronous development and multiple generations throughout the year such that adults are found almost year round.