Caddisfly Welfare: Builders of the Freshwater World

Caddisflies construct elaborate larval cases from stones, sand, and plant material. These ecosystem engineers are sensitive indicators of freshwater health and face threats from pollution and warming.

Key Facts

Caddisfly larvae build protective cases from materials in their environment, bound with silk
Over 14,500 species of caddisfly are known, inhabiting freshwater ecosystems worldwide
Many species are highly specialised for particular stream conditions including temperature and flow rate
Caddisfly larvae are a primary food source for trout and salmon in cold-water rivers
Some caddisfly species have declined by over 80% in intensively farmed river catchments

Welfare Considerations

Caddisfly larvae invest significant energy in building and maintaining their cases, a behaviour that suggests complex sensory integration and environmental responsiveness. Pollution disrupts case-building and impairs larval development. Pesticide runoff from farmland causes acute toxicity events. Temperature increases above species-specific tolerance thresholds prevent successful pupation. Their role as ecosystem engineers means their welfare is tightly coupled to the broader health of freshwater communities.

What You Can Do

Reduce pesticide and herbicide use near freshwater bodies
Support farmed land buffer strips that filter runoff before it reaches rivers
Participate in stream surveys to monitor caddisfly diversity as a health indicator
Advocate for stronger agricultural water quality regulations in river catchments