(Big) Bug of the Month: Terrestrials

August. Mid-way through summer. For anglers, this means that we face warmer water temps, afternoon heat, and messy fly boxes. August also means that we can add some larger bugs to the menu. We may not completely abandon the smaller dry flies of July (such as the Trico), but we definitely add terrestrial patterns to the mix. For our August Bug of the Month, we literally go big or go home and start presenting terrestrial patterns to wary trout.

Terrestrial Factoids

Of course, we use the word “terrestrial” as a broader umbrella term.  We’re talking ants, beetles, inchworms, grasshoppers. As we head into and through the “dog days” of summer, warmer and often drier days, the big bugs come into play.

Terrestrials will warm themselves in the sun to get their body temperature up. These big-eyed, large-winged, bugs will become more active as the day, and their hefty bodies, warm up.

And the landscape for these bigger protein sources are as varied as the bugs themselves.  Wind-swept meadows like the Dream Stream and banks lined with willows all offer the food sources for the various terrestrials. Add a little breeze and the morning dew evaporating as the day warms, and you have the combo for serving up these bigger meals.

Fishing the Terrestrial

While the Trico and other small dry flies usually demand a more delicate presentation, terrestrial patterns allow us the chance to be a little more aggressive.  Grasshoppers, beetles, ants, and other “land-locked insects” are not supposed to be in the water.  They get blown off the vegetation on the bank or maybe just simply knocked off. They may land with a bit of a splash. As long as your leader and fly line are not splashing down with too much energy, a little “splat” is not a bad thing with your beetle, ant, or hopper.

Fishing terrestrials is not dissimilar to fishing dries since they are, mostly, fished on the surface. (I say “mostly” because there are techniques for fishing drowned terrestrial sub-surface that can be productive.) Vegetation, undercut banks, and overhanging structures like tree limbs or remains of bridges offer protection for trout and opportunities for terrestrial action. Getting your cast closer to the bank or these structures can produce a strike – and have that chance for a good sized Brown trout taking the offering. If you’re not getting your bug hung up on the grasses along the bank, you’re probably not being aggressive enough.

Terrestrials will also get pushed out to the middle of the river, so don’t be afraid to cover water from the bank to those mid-river runs. Their drift in the current may even be a little erratic, so don’t be afraid to give your bug some movement, too. A little twitch to imitate a struggling hopper can be effective, but don’t overdo it or you might get an otherwise interested trout to become wary.

Tips for Terrestrials

99% of the time, especially fishing dries, the “w” word is our enemy.  Not so when it comes to fishing terrestrials. A little breeze, even a gust or two, can offer the kind of conditions where terrestrials are more likely to hit the water.

Remember, too, that there is not a “terrestrial hatch.” While some mayfly hatches may die down as the day progresses, you might have better chances to fish a terrestrial into the late morning and throughout the afternoon. In addition, you may not see a fish steadily rising to terrestrials as you might when there is a trico or BWO hatch. You won’t see a cloud of terrestrials above the water (although that visual creates quite a picture!). We rely on the more opportunistic feeding habits of trout when we present a terrestrial to them.

We hear “hopper-dropper” at this time of year for good reason. Why not trail a smaller dry fly off of that Amy’s Ant or maybe drop a small emerger?  The buoyancy of the hopper provides a stable platform to offer other items on the menu. On the best days, you’ll get action on both the hopper and the dropper and nothing beats that.

Tying the Terrestrial

So many choices and directions to go with terrestrials.  Here are a few of our favorite patterns:

Final thoughts

While fishing terrestrial patterns is no secret as we move deeper into the heat of summer and then into the fall, the versatility that these large bugs offers is sometimes overlooked.  Whether fishing them alone, or as the lead fly in a hopper-dropper rig, or even “drowning” them; or fishing them tight against the bank or out in the middle riffles of the river, terrestrials rejuvenate our game just as we hit the dog days of summer.