Many trout couldn’t live without terrestrials! When the aquatic insect hatches are over for the season the trout live on the great profusion of these land born insects.
Serious trout anglers to to a great amount of study in learning to identify the mayflies, stoneflies and caddisflies. We learn their hatching periods, the habits of their nymphs and their mating habits. Personally I find this fascinating and I follow it every year and select my artificial flies to match these.
However, once the hatches of aquatic insects are over, my interest switches to the great numbers of terrestrial insects the trout are now feeding upon. I know there are over two hundred types of beetles along our trout streams and the trout feed on all of them. Experience has shown me that these trout will seldom pass up a Murray’s Flying Beetle drifting over their head no matter which beetles they have been feeding upon all day.
A simple but very effective technique which works well for me is to simply study the natural insects along the banks and then tie on a fly which matches these. For example, there are many natural ants along the stream. I’ll put on a Mr. Rapidan Ant and catch many nice trout. If there are many wasp buzzing about the stream, then I put on a Shenk’s Cricket.
I personally don’t feel I need to identify all of the terrestrial insects I see around our trout streams. Simply going to my fly box and selecting a fly which matches the naturals works for me.