Bug, and larvae questions.

[tjm]

Sounds like a place to use a Black Nose Dace or a Mickey Finn. I have often found that the best hatch match is something entirely different. But the Yellowstone is one of those places that I fished and never saw even a minor hatch. Also one I'll likely never see again. 

[ness]

From ChatGPT

Got it — let’s walk through the life cycles of the most important aquatic insects for trout fishing, and pair each stage with the common fly patterns that imitate them.

 

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1. Mayflies (Order: Ephemeroptera)

 

Life cycle stages important to anglers:

1. Nymph – lives underwater, crawls or swims.

2. Emerger – nymph hatching into adult on or just below surface.

3. Dun – first winged stage; rides the surface to dry wings.

4. Spinner – mating stage; falls spent on surface.

 

Fly patterns:

 

Stage Common Fly Patterns

Nymph Hare’s Ear Nymph, Pheasant Tail Nymph

Emerger RS2, CDC Emerger, Soft Hackle

Dun Adams, Comparadun, Sparkle Dun

Spinner Rusty Spinner, Poly Spinner

 

 

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2. Caddisflies (Order: Trichoptera)

 

Life cycle:

1. Larva – worm-like; some in cases, some free-living.

2. Pupa – transformation stage; swims to surface.

3. Adult – skitters on surface or lays eggs.

 

Fly patterns:

 

Stage Common Fly Patterns

Larva Green Rockworm, Caddis Larva

Pupa LaFontaine’s Sparkle Pupa, Soft Hackle Caddis

Adult Elk Hair Caddis, X-Caddis, Goddard Caddis

 

 

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3. Stoneflies (Order: Plecoptera)

 

Life cycle:

1. Nymph – lives under rocks, crawls to shore to hatch.

2. Adult – large, clumsy flyer; lays eggs by dipping abdomen.

 

Fly patterns:

 

Stage Common Fly Patterns

Nymph Kaufmann’s Stone, Pat’s Rubber Legs

Adult Stimulator, Sofa Pillow, Chubby Chernobyl

 

 

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4. Midges (Order: Diptera)

 

Life cycle:

1. Larva – tiny worm-like form.

2. Pupa – rises slowly to surface.

3. Adult – very small mosquito-like insect.

 

Fly patterns:

 

Stage Common Fly Patterns

Larva Zebra Midge, Brassie

Pupa Black Beauty, WD-40

Adult Griffith’s Gnat, Parachute Midge

 

 

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5. Aquatic Terrestrial Crossovers (e.g., Grasshoppers, Ants, Beetles)

 

While not aquatic, they fall into water often in summer.

Fly patterns: Parachute Hopper, Foam Ant, Beetle Bug.

 

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Diagram Style Overview

 

Imagine each life cycle as a loop:

• Mayflies: Nymph → Emerger → Dun → Spinner

• Caddisflies: Larva → Pupa → Adult

• Stoneflies: Nymph → Adult

• Midges: Larva → Pupa → Adult

 

If you want, I can make you a visual chart that shows each insect’s life cycle in diagram form with fly pattern names beside each stage so it’s quick to reference streamside.

 

Do you want me to build that chart next?

[tjm]

Mayfly duns also called Subimago, spinners called Imago, Mayflies are also called "shadflies" or "fishflies" in some locations/literature.  Mayfly nymphs are the larval stage, mayflies skip the pupal stage, and nymphs are sometimes called naiads in literature on mayflies because in Greek mythology naiads were nymphs associated with fresh water. You may see the stages of an insect's life called "instars". The transformation between instars/stages, "molting",  is a time vulnerability when fish find it easy to catch the bugs. 

Small Griffith's Gnat does not represent a single midge, in the way that Zebra Midge or Rootbeer Midge does,  but, rather a cluster of adult midges with each fiber of the hackle being a single midge. Clustering is a common midge behavior as the new adults adjust to a new form.  It's why I can use a size 18 rather than size 24 or smaller hook. But in larger sizes #14 might better be used as a caddis, #12 as a spent mayfly. 

The most common caddis larvae that I see are the tiny cased worms in their sand built houses on bottoms of rocks and I've never tried to imitate them, imo, the caddis pupa as it rises is the most vulnerable stage and the one I imitate most often, with sparsely tied spider/flymph/soft hackle flies.

A couple of sites that at a glance  I suspect are AI generated but seem to have good pics and cover most of the entomology that an angler needs to be familiar with

https://flyfishcircle.com/entomology  (Images are links to more details) 

https://minturnanglers.com/basic-fly-fishing-entomology-bugs-flies/