How Serious Are Caddisflies? These pests are not harmful to people. However, they may swarm in large numbers and are very attracted to lights. It is this swarming behavior that makes them pests, plus the reported occurrences of allergic reactions and asthma that are associated with their presence.

Why is the Caddisfly important?

Caddisfly larvae represent an important ecological component of nutrient processing and energy flow in lakes and rivers and provide a food source for a variety of aquatic predators, such as trout and other fish (Resh and Rosenberg, 1984; Johansson, 1991; Wiggins, 1996a).

What is the lifespan of a Caddisfly?

Adults usually stay close to the water, and adult females lay eggs on or in the water (females of some species will dive underwater to lay eggs). Some females will lay up to 800 eggs. Like many aquatic insects, caddisflies live most of their lives in the larval stage, often 1 or 2 years.