While most gardeners are always on the look out for bugs, fly fishers are as well. Gardeners try to determine if they are good or bad, anglers try to determine if they would be fish food. The very astute gardeners will observe them, take closeup pictures of them [ESP], and learn about them. If they are good, whoo hoo, if they are bad, squish. Astute fly fishers will observe them, take close up pictures of them and learn about them. If they are bad you just toss them, if they are good, [aka fish food] then you copy them.
There are two lines of thought on making bugs that catch fish. Some tie the bugs to sorta look like the bug they want to fish with. Fish aren't too smart and that is really good enough. However there is another group of fly tiers that fish with bugs that are realistic looking.
I know several people that do this and their bugs are just unbelievable. They are just so realistic looking and they also are tough. They will hold up to getting cast back and forth in the air as well as getting wet and getting mauled by fish.
I thought it would be interesting to show some pictures to gardeners of some of the bugs that these guys make. They are unbelievable in their looks as well as being fishable. I got most of these pictures off of flytyingforum.com if anyone wants to check them out.