Hello all. Regarding sampling aquatic insects in our local streams, I was wondering how diverse the variety of insects are from season to season. What I mean is that if I were to enter the streamduring the winter months and seine up aquatic insects would I be likely to find the same sampling of insects during the spring or would possibly some major species of nymph be missing? I realize that some of the nymphs might be a bit larger in the spring but does anyone know if I would be missing any significant species of nymphs that may only be present during the spring or summer months?

What I'm getting at is that over the winter I was thinking of doing some stream samplings and then trying to tie up some flies to mimic those samplings. I would hate to tie up a number of nymphs only to find out that a major species has a very short lifespan and thus might only be present in nymph form during the spring or summer months. Again I am not talking about emerging or adult insects but only the nymph. I have purchased a few hatch books which make reference to different nymphs in a stream but have not found any reference on how long the nymph may reside in the stream before hatching. Any insight would be appreciated