They also found that over 95% of specimens
caught in traps were known to occur as larvae in the sampled stream. Petersen et al.
(1999) placed a total of 15 malaise traps at 15 m intervals from a studied stream and
found that over 90% of caddisfly specimens were caught within 15 m of the sampled
stream. They further found an exponential decline in caddisfly specimen abundance as
distance from the stream increased.