Four Reasons to Fish Imitations of Impaired Insects

Four Reasons to Fish Imitations of Impaired Insects

Four Reasons to Fish Imitations of Impaired Insects

While giving fly tying demonstrations over the weekend at the Wasatch Fly Tying and Fly Fishing Expo in Salt Lake City, I mentioned to several people observing me tie that I almost always fish imitations of insects that are in some way impaired. What do I mean? I am referring to flies imitating or at least suggesting aquatic insects that are emerging, crippled, spent, drowned, or waterlogged, or of any terrestrial insects that fall in the water (since land insects in the water are by their nature in trouble). Here are five reasons to fish flies meeting one of the above criteria.

Trout Prefer Them

This is the most obvious and important reason to use such flies. Various studies on trout feeding behavior find that they prefer to feed on insects during their life stages in which they’re in trouble, or on individual insects that are experiencing difficulty. For example, they’ll emerging or crippled insects in preference to adults, and they’ll eat dun mayflies that have been knocked over in preference to those riding “like little sailboats” upright, as they’re often described.

The reason trout prefer insects that are in trouble is simple. They’re less likely to get away. Each time a trout rises to eat an insect and it flies away, that’s a calorie the trout has wasted. Over evolutionary timescales, it has made more sense for fish to key on bugs that are less likely to get away and more likely to prove an easy meal. The smaller the insects, the more important this is. So trout really prefer spent, crippled, emerging, or otherwise distressed ants, PMD, BWO, midges, and tiny caddis over their healthy brethren.

Flies Will “Behave” Impaired Anyway

This is a more esoteric reason. Look at a healthy dun mayfly. It rides up on its tippy-toes, above rather than in the surface film. Many flies were nominally designed to match this behavior. The classic Catskill-style mayfly dry is a perfect example. Drop it dry on a glass of water and it’ll ride high, just like the real bug.

Yet in fishing situations, no fly pattern will ride as high as healthy naturals, at least not for long. All flies get waterlogged, ragged, chewed-on, and otherwise stop looking like they do in the fly shop display within minutes or seconds of being tied on the end of your line. In other words, they start looking and behaving more like distressed insects, no matter what you do. This partially explains the common phenomenon of a fly working better the more beat-up it gets.

If your fly is going to look and act distressed anyway, why not emphasize these attributes, rather than trying to minimize them?

They are Fast and Easy to Tie

Look at any fly intended to represent a mayfly emerger, cripple, or spinner. Look at spent caddis patterns. Look at most traditional “fur and feather” ant imitations. They’re all dirt simple. Even many foam grasshopper imitations likewise aren’t very complicated, even if they’re large. Most utilize less than a handful of materials, and often rely on synthetic materials with hints of flash or sparkle that are easy to work with and cheap to buy. Here are some examples, none of which take me more than three minutes to tie:

caddis cripple

This caddis cripple pattern uses three materials (in addition to thread and hook): dubbing, a synthetic yarn, and hackle. When tied to match the important Nectopsyche caddis on the Firehole, it’s my #2 dry on that river. When tied in tan, it imitates both emerging and egg-laying tanĀ Hydropsyche caddis, the most important summer caddis in the entire region. In pink, it’s a great attractor for bright summer days on the Yellowstone.

purple hazy cripple

This attractor suggestive of a mayfly cripple uses five materials: a synthetic yarn for the tail, spandex for the body, a different synthetic yarn for the wing, and two colors of hackle (Adams-style). Since both bunches of synthetic yarn or tied in as clumps and then trimmed to shape, this is a much faster fly to tie than the original Purple Haze Parachute on which it’s based. It’s also three times as effective. It has been our top dry fly period since the fall of 2009.

flying ant

This is our top-producing terrestrial pattern most seasons. It uses three materials: acrylic yarn chopped into dubbing in a coffee grinder, synthetic yarn, and a brown hackle. We use these everywhere, from little mountain creeks to the roaring Yellowstone. I can whip one out in about two minutes.

I went a little long in this point, but it’ll tie in with my next post on the subject (expect it around April 20-22), which will be about designing and tying patterns that match impaired bugs.

Most Anglers Use Something Else

Think about the dry flies that fill fly shop bins, especially those considered classics and standbys. They’re generally bushier and more complicated. This applies to everything from mayfly imitations and attractors suggestive of mayflies (Adams, Royal Wulff) to caddis (Elk Hair Caddis) to stoneflies (big foam monstrosities and Stimulators) to terrestrials (big complicated foam hoppers and most ants). These flies generally aim to suggest healthy dun or adult aquatic insects and terrestrials that haven’t started to succumb to their unplanned swim. While it doesn’t matter on lightly-pressured waters, opting to suggest something else will earn you more confident strikes and more fish.

As noted briefly above, my next post will cover tips on how to create flies that match impaired insects.

Leave a Reply