Some caddis fly species are tolerant of slight pollution.
We particularly needed to gather together this group of experts to be sure than any adult caddis found were indeed Land Caddis.
The size, the material used and how its case has been constructed can identify each sub species of cased caddis.
caddis larvae build cases that are two ir three times the normal width?
caddis flies spend the larval stage of their development in a case on the bed of a stream.