Caddisfly

Caddisflies (order Trichoptera) are a group of insects closely related to moths (order Lepidoptera). Their name is derived from the larvae's characteristic habit of constructing protective cases (or "caddises") around their bodies using silk and materials found in their aquatic environment, such as small stones, twigs, sand grains, and shells.

Life Cycle

Caddisflies undergo complete metamorphosis, with an egg, larval, pupal, and adult stage. The life cycle is typically aquatic, with only the adult stage being terrestrial and relatively short-lived, primarily focused on reproduction.

• Eggs: Caddisfly eggs are usually laid in masses in or near water. The egg masses can be gelatinous or attached to submerged objects.

• Larvae: Caddisfly larvae are aquatic and highly diverse in appearance and behavior. They are characterized by a sclerotized (hardened) head and thorax, and a soft abdomen. Many species construct portable cases using silk and available materials, providing protection and camouflage. Other species are free-living or construct fixed retreats on rocks or other substrates. Larvae are typically herbivores, detritivores, or predators, playing important roles in aquatic food webs.

• Pupa: The caddisfly larva pupates inside its case (or a modified version of it). The pupa is an active stage with functional mandibles used to cut its way out of the case and swim to the water's surface.

• Adult: Adult caddisflies are typically moth-like in appearance, with hairy wings that are held roof-like over their body when at rest. They are generally weak fliers and are most active at dusk or night. Adults do not feed extensively and their primary function is reproduction. They are often attracted to light.

Ecology

Caddisflies are important indicators of water quality. Their presence and diversity are often used in biomonitoring programs to assess the health of aquatic ecosystems. Many species are sensitive to pollution and habitat disturbance. They also serve as an important food source for fish and other aquatic animals.

Classification

The order Trichoptera is divided into several suborders and families, reflecting the great diversity of caddisflies worldwide. Classification is based on morphological characteristics of the larvae and adults, as well as molecular data.