Have you ever seen one of these? Do you know what it is?
A caddisfly is a really neat aquatic insect that is common on rivers and streams throughout the world and Rocky Mountains. Here are 7 caddisfly facts.
I first started learning about caddisflies when I got into fly fishing. As a fly fisher you need to know about the different aquatic insects so you can figure out what the fish are eating. The more I learned about caddisflies the more I liked them. Similar to mayflies and stoneflies you can find them on the bottom of rocks in rivers and streams. However, there are a few things that make a caddisfly unique.
7 Caddisfly Facts
This is an aquatic insect that lives most of its life underwater and part of it as a winged adult (quick reminder, all insects undergo metamorphosis). These bugs live as a nymph under water in streams, rivers, and lakes for up to two years. Then when ready, they pupate into an adult inside of their case and split the case. After that they swim to the surface of the water where they emerge from the water and fly off. They must do this quickly because fish and other animals are looking to eat them!
Caddisflies build protective cases around their bodies. Photo via Flickr.
The nymphs of larvae of caddisflies are what is so unique about these insects. They use silk from their body to build protective cases around their soft bodies to protect them. These cases are made of pebbles, sand and plant material.
These tiny insects play an important role in river ecosystems. They are an important food source for fish (both the nymphs and adults). I’ve seen trout jumping up to two feet out of the water to eat some caddisflies! The nymphs are also eaten by a unique bird – the American dipper, which walks underwater on the bottom of streams and rivers. The adults are a food source for birds, amphibians, and reptiles.
There are more than 1,000 species of caddisflies in North America and over 7,000 in the world.
An adult caddisfly does not live very long. The nymphs live underwater for up to two years, but the winged adults only live for a few weeks to months at the most. The adults don’t have developed mouth parts and are only able to sip liquids for their food, such as nectar. Their primary purpose is to reproduce.
Some species of caddisflies use the silk from their body to create nets. These nets go out from their cases into the moving water. The water flow brings food particles into the net, which get captured and are eaten.
When at rest the wings look like a little tent over its back. Photo via Flickr.
Caddisflies are closely related to moths and butterflies. An adult caddisfly looks similar in appearance to a moth when flying. It has a furry body, but short compact wings. When at rest the wings are folded over the top of its body like a tent.