Caddisflies (order Trichoptera) are small, moth-like insects closely related to butterflies and moths (order Lepidoptera). They are named for the cases (portable shelters) that many larval species construct from silk and environmental materials like sand, pebbles, or plant debris. Here’s an overview of their key features:

Life Cycle & Ecology

Eggs: Laid in gelatinous masses on or near water.
Larvae: Aquatic, living in freshwater habitats (streams, rivers, ponds).
Many build protective cases (e.g., from sticks, stones, or silk tubes).
Some are free-living or spin nets to catch food.
Feed on algae, detritus, or small invertebrates.

Pupae: Develop underwater inside the larval case or a cocoon.
Adults: Short-lived (1–2 weeks), resembling moths but with hairy wings (Lepidoptera have scaly wings).

Key Characteristics

Larvae:
Soft-bodied with six legs and often gills on the abdomen.
Case-building species are important bioindicators of water quality.

Adults:
Nocturnal, attracted to light.
Mouthparts reduced (some don’t feed).

Ecological Importance

Food source: Vital for fish (e.g., trout) and other aquatic predators.
Water quality indicators: Sensitive to pollution; used in biomonitoring.
Silk production: Some larvae produce silk stronger than spider silk.

Fun Facts

Some species are used as fishing bait ("caddis flies").
Artists like Hubert Duprat collaborate with caddisfly larvae to create jewelry by providing them with gold or gemstones for case-building.

Would you like details on a specific aspect (e.g., case-building behavior, taxonomy, or their role in ecosystems)?