Trichoptera (caddisflies) are diverse in their habitats are the most diverse and abundant organisms in freshwater habitats. They are important trout food sources and generally are the majority of what trout eat.
Trichoptera comes from the Greek words for hairy wings; and with close inspection, this description is very appropriate. Caddisflies often look like a moth. They undergo the same metamorphosis as moths and butterflies do. In fact, moths, butterflies and caddisflies are classified under the superfamily Amphiesmenoptera, meaning “dressed up wing.” Trichoptera diverted from this evolutionary path when they developed respiratory systems that allowed them to be aquatic.
Trichoptera is a small order, with only about 11,500 known species worldwide but there is an estimated 30,000 yet to be described species! There are 26 known North American families with 23 of these familiar found in the eastern US.
Their life cycle of most is one year and that begins with the initial laying of the egg! There are a few that take two years to mature. Caddis larvae have a large range of temperatures, water quality, oxygen levels, food availability, and water currents in which they can survive and thrive. Most eggs will hatch in 2-4 weeks although some take 9 months. Once hatched, the larvae have 5 stages of growth (called instars), normally this takes 6-10 months. Equally unique is that each larva creates a distinctive case or shelter in which it will pupate.
Adult caddis live 1-4 weeks, depending on the weather conditions after they emerge. Once females are ready to lay their eggs, they tend to return to their larval site. There are 4 basic egg-laying behaviors: 1) laying eggs beneath the water, 2) laying eggs on the water’s surface, 3) doing both, and 4) laying eggs at the edges of water.
Identification of Trichoptera is difficult. For the vast majority of caddis you cannot confidently use color. We may know the larvae and we may know the adults, but we know little about which larva turns into which adult. It’s estimated that a little over 33% of the adults have been matched to their larvae. Dave Ruiter, an caddisfly expert, says the The North American caddis literature to the species level is in shambles. here are a couple books that cover the caddis genera fairly well as adults and larvae. But the species level literature requires numerous bookcases/file cabinets. Most all Trichoptera females are tougher to determine to species than males. In many genera (Nectopsyche, Wormaldia and others) they may be impossible to determine without using DNA. And many females have yet to be associated with their male.
Hydropsychidae (Netspinning Caddisflies)
Leucotrichia sp – Ring Horn Microcaddis
Lepidostomatidae (Bizarre Caddisflies)
Leptoceridae (Long-horned Caddiflies)
Limnephilidae (Northern Caddisflies)
Hydatophylax argus – Giant Cream Pattern wing Sedge
Phryganeidae (Giant Casemakers)
This family of caddisflies make their habitats in everything from cool flowing water to warm flowing water, from ponds & lakes to temporary pools. The larvae are swift and will leave their case if disturbed. Some will return to the same one, others will use another option. Their cases are smooth cylinders made from plant debris, sometimes arranged in a neat spiral.
Phryganea sp – Giant Casemaker
Ptilostomis ocellifera – Giant Rusty Sedge Caddisfly
These seem to be able to thrive is most any habitat, which is unusual because they are considered a “primitive” genus. They are the most common of the 4 North American species
Uenoidae (Stonecase Caddisflies)
Neophylax sp – Autumn Mottled Sedge