Be careful to learn the habits of the most common insects in their various stages. For example, some insects hatch in the afternoon or at night; therefore, you don’t need to fish them during the early part of the day. But most important is WHERE DO INSECTS HATCH?
Where do most mayflies hatch?
Answer: Even the clingers that live in the fast water runs and riffles move to the
slow moving water of calmer pockets and shallow water that is near banks and
behind boulders to hatch. Just about all the crawlers and swimmers move to slow
to moderately moving water to hatch.
Where do the stoneflies hatch?
Answer: They actually hatch out of the water. They move out of their fast water
habitat into slower, shallower water to crawl out of the water and hatch on the banks
and rocks.
Where do the caddisflies hatch?
Answer: All the different species move to the slow to moderately flowing water for
their pupae to emerge.
To summarize: Almost all aquatic insects hatch in moderate to calm water which can be close to the faster water or perhaps several feet away from the fast water. When trout feed in the slow to moderately flowing sections of the streams; or eddies, pools, the ends of runs and riffles and calm pockets that are within the fast flowing freestone streams, they can examine the fly much closer.