Mayfly vs. Caddis

[Joe Billingsley]

I was on a plane this weekend and someone had left a magazine there that had an article in it about wingless wets (I wish I could remember who wrote it). The author said that when tying them all you have to do to change a basic pattern from a mayfly imitation to a caddis imitation is to make the hackle collar a little bit fuller and thicker.
I know that is a simplification, but do you think that is basically true?
Joe

[narcodog]

If you are talking about a dry to a wet, I think that a change in the type of hackle is necessary. As well as color, most caddis are a shade of black, brown or tan with a few exceptions.

[Joe Billingsley]

He, or she, was writing about wingless wets only.
Joe

[Old Hat]

I like to add a peacock head. And you would want to nix the tail of the mayfly pattern. I don't think that just a denser hackle would get you too far closer to a caddis.

[William Anderson]

One size fits all? Now that just takes all the fun out of it doesn't it. But seriously...if you're at all interested in matching an insect, and you believe silhouette has any significance in fly design...caddis are fat and shaped differently than mayflies. Hackle or no hackle, no?

1. presentation
2. size
3. silhouette
4. behavior
5. color

9. hackle thickness.

I'm not sure how helpful such an over-simplification could be. caddis certainly behave completely different from mayflies. And the silhouette is quite different. Any other thoughts? It's an interesting question.

[redietz]

...caddis are fat and shaped differently than mayflies.

That, to me is the biggest difference between flies I use for caddis and flies I use for mayflies. In the former, I want a heavily dubbed or peacock herl body. For the latter, I want a thread or lightly touch dubbed body (usually -- there are exceptions). Fat vs. slim is the only concession I make to insect order.

[Joe Billingsley]

I agree with what everyone has said (especially William: "Now that just takes all the fun out of it"!). However, I do think the difference between a "fat" bodied #18 caddis and a "thin" bodied #18 mayfly is very small and may just be in the eyes of the discerning tyer. I think that was what the author was getting at. The larger the fly, the more it could make a difference. I have always dressed a wet fly that I meant to be a mayfly imitation with sparse hackle to get that dainty look and a caddis imitation with thicker hackle to get that "drowned cat" appearance. What kind of fly the fish think they are, other than just dinner, I wish I knew.....or do I?
Joe