A. If you've read any of my previous responses concerning insect hatching and temperature, you'll know that aquatic insects require a certain number of degree-days to hatch; when they have experienced the required number, they hatch, regardless of whether it is high noon, evening, hot, or cool. Some insects respond to various light conditions and emerge more readily when the preferred light conditions are present; that might explain why the caddis in N. California emerge under low light conditions. Again, many of these traits are species-specific, so it is hard to generalize on some of these things. The reluctant trout may find plenty to feed on in the deeper waters, thus they don't have any reason to chase hatches - that's a guess.