Meeting the Late Summer Challenge

By Jeff Morgan

Late summer brings new challenges for Western dry fly anglers. The big hatches are either fading fast or occur at times when anglers aren't on the water. Further, most trout have been hooked, caught, or spooked a more than few times since April and are now super-wary and ultra-critical of whatever you lob their way. On top of it all, angling pressure peaks in August.

While many anglers turn to grasshoppers to prospect in the hatchless waters of mid- to late-summer, they only exacerbate the problem. Hoppers, in general, are a tiny component of the trout diet. Large hoppers (size 10 or bigger)--the kinds most anglers fish and most shops sell--are rarely found in trout stomach samples. Even in the legendary "hopper water" of the Madison and Yellowstone, hoppers make up less than 1% of the annual diet of trout.

Despite this biological reality, anglers bombard the water with hoppers when another insect is far more important. That insect is the terrestrial beetle .

Eaten Far More Often than Hoppers

Scientific studies reveal that terrestrial beetles are three to seven times more common in trout diets than grasshoppers. Secondly, beetles are an exceedingly diverse order of insects; just the family Curculionidae has more species than the total number of vertebrate species in the world! One study on Oregon's Lookout Creek found over 4,000 species of beetles in a one-mile stretch of riparian zone. The third reason for beetle importance is that most anglers don't imitate them, so trout haven't seen a plethora of fake beetles.

These three factors combine to make beetles extremely important to fly anglers.

I became a beetle addict after seeing how well they work on highly-pressured summer trout water such as the Henry's Fork, the Yellowstone region, the Green River, and the many streams in the Missoula area. No other patterns brought the consistent success and confident rises that beetle imitations elicited.

And beetles are not just a food for stream trout. In late June, I sampled five trout at Oregon's Timothy Lake (all caught on streamers), and the dominant food was terrestrial beetles. I counted nine different genera, ranging from a size 20 black whirligig beetle to a size 12 bright green beetle.

Exploiting the Fly Shop Monoculture

In the world of beetle imitations, anglers who don't tie their own flies have a problem: the diversity and importance of beetles is not reflected in fly shop bins. Most shops carry one or two beetle patterns (usually some variation of the Black Foam Beetle ), in size 12-16. As a fly tyer, you can exploit this monoculture of imitations by tying both tiny patterns (size 20-24) and excessively large patterns (size 4-10), as well as carrying an array of body shapes (narrow, round, etc.) and colors.

I pack a full box stocked exclusively with an eclectic selection of beetle imitations, and by the end of the season, that box of 175-200 flies is almost empty!

Exploiting Size Diversity

As mentioned earlier, diversity of size is critical with beetle patterns. Even anglers who use beetles are usually tossing size 14-16 flies. This is a human choice, not a fish choice, because you'll encounter just as many size 20 and size 10 beetles as size 14 beetles in stomach samples.

My most effective beetle imitations are at the extreme ends of the size spectrum: size 20-24 and size 8-10. These sizes mimic insects that are just as common as medium-sized beetles, but few highly-pressured trout have seen an imitation in those sizes.

Tying both small and large sizes requires creative thinking and problem solving. For tiny beetles, keep the fly as simple as possible. A tiny foam-backed pattern (ala the Ladybird Beetle ) with a sparsely dubbed body and few steps is a common route to take. A small, peacock-bodied beetle, such as the CDC Baby Beetle , is another simple pattern that takes just a minute or two to tie. Both patterns float well due to the small, light-weight hook.

Jumbo-sized imitation, on the other hand, often needs a lifejacket and half a bottle of Gink to keep them on the surface. Here, a foam underbody and a foam overbody are useful. The Coleoptera Colossus requires serious aid to keep the size 8 (or larger) hook afloat.

DON'T BE AFRAID OF BIG BEETLES. The only reason you don't see them in shops is because . . . well, once you tie a size 8 beetle you'll realize why they don't sell well.

Exploiting Color Diversity

Color is something that should be altered as well. Ninety-nine percent of patterns in shops or books are either black or peacock. This ignores the hundreds of thousands of beetle species that exhibit different color schemes. All-brown patterns are essential, though all-green patterns are useful too, as are yellow-back, orange-back, and blue-back patterns.

Tying Beetle Patterns

Beetles are some of the most fun flies to tie because there is no "right" pattern formula. Some of the strangest, "ugliest" patterns turn out to be the best!

Tying materials for beetles is limited only by your imagination. The core materials--foam, peacock herl, sparkle dubbing, hackle, and black deer hair--offers the tier dozens of options. Throw in rubber legs, ostrich herl, paints, Krystalflash, Flashabou, CDC, and even coffee beans (a split coffee bean floats and looks almost exactly like a beetle) and you've got even more options.

Of all the fly patterns in this article, the most glaringly "gimmicky" is the ladybug, but it is an essential pattern. Ladybug beetles can appear in thick densities in areas with high aphid populations, especially clearcuts, gardens, and some farming operations. Here, trout will ignore black beetle imitations of the proper size but freely rise to ladybug imitations. Even on places like Slough Creek, miles from any of those environmental alterations, I have had trout that rejected several beetle imitations succumb to a ladybug. If ever restricted to five beetle patterns, the ladybug would undoubtedly be part of the starting lineup.

One complaint that many anglers have is that they cannot see their beetles on the water. The common solution is to add a tuft of orange yarn to the back of the fly. Unfortunately this orange tuft is visible to the fish, too. As the fly approaches the window of the trout, the orange tuft is obviously visible.

Instead, simply put a dab of orange or chartreuse paint or fingernail polish on the back of the fly. It makes the fly just as visible, and it is something you can optionally add to your patterns down the road.

Tying Instructions

Click the links below for tying and fishing instructions.

Ladybird Beetle
Rubber Leg Beetle
CDC Baby Beetle
Coleoptera Colossus

Jeff Morgan has written many articles for Westfly, mostly on entomology and fly tying. He is the author of An Angler's Guide to the Oregon Cascades and Small Stream Fly Fishing.