Upper Delaware river insects, caddis fly insect identification for fly fishing caddis flies.

Order Trichoptera - Caddis Flies

Select a Caddis Fly from the drop down menu below.

   Caddis flies are by far the largest group of aquatic insects, with estimates of nearly 50,000 species world wide, with well over 12,00 species in North America. Caddis are also by far the most complex, with each genus widely varying in type of case, and pupation habits. Some build portable cases, and abandon them, building new ones as they grow, others build fixed cases, others are free living, and don't build cases until their final instar. Cases are constructed from various materials, and are constructed, and attached to the substrate by means of spinning silk thread. Cases differ greatly, to the point of some species building cases from different materials at different larval growth stages. Most caddis hatches are thickest during warm sunny days, the sun triggers the hatch by creating a greenhouse like effect through the water, warming the larval case.

   Most species have a univoltine life cycle, very few have multiple broods during the same season. Caddis adults live for a few days to a couple of months after mating, and egg laying flights. Others like Frenesia emerge late in the season, (November - December) and live in the adult stage throughout the winter, with mating, and egg laying flights taking place the next spring. Adult Caddis flies find sustenance in the form of pollen, and plant matter.

   Caddis flies inhabit a wide range of environments, with some species being much more tolerant of pollution than are Mayflies, and Stone flies.

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Delaware River fly fishing with Jerry Hadden.