THEORETICAL MECHANICS OF PARTICLE CAPTURE - PREDICTIONS FOR HYDROPSYCHID CADDISFLY DISTRIBUTIONAL ECOLOGY

Nets with fine meshes capture suspended particles at a higher rate per unit of area than those with larger meshes. Species spinning large meshes have a greater total capture rate because of a correlation between mesh size and overall net area. Capture rates of all nets increase with current speed and temperature. A specific mesh size maximizes the capture rate of a given particle size (for a fixed ambient current velocity and fiber diameter). Nets with larger meshes have a greater tendency to capture larger particles, and nets with smaller meshes have a greater tendency to capture smaller particles. Results are compatible with a particle-size hypothesis, but they compel a modification of a capture-rate hypothesis, suggesting that the particle-capture performance of different net morphologies is not a sufficient basis for explaining empirical correlations between resource concentration and caddisfly community structure. -from Authors