ROCK CREEK - You don't have to be an entomologist to appreciate Pteronarcys californica, the Latin name of an oversized aquatic insect better known to Rocky Mountain anglers as the salmonfly.
To any veteran fly-fisher, word of the salmonfly hatch elicits mental images of gargantuan trout slashing from the river's depths to engulf the fluttering bugs - and the plethora of assorted imitations that have been dreamt up by creative fly-tiers - as they struggle on the surface.
As she's done every June since moving to the area in 1997, Six headed up Rock Creek last week chasing the salmonfly hatch.
But for Six, who is an entomologist in the School of Forestry at the University of Montana, the salmonflies are as much the object of the quest as are the trout. If push came to shove, she'd probably just as soon catch a trophy salmonfly as a trophy brown or rainbow.
"I love those bugs," she says. "They're pretty awesome. I didn't even get any fishing done the first day I fished the salmonfly hatch here. I was too interested in the bugs. They're incredible. I'd never seen any aquatics that big."
That first outing up Rock Creek, Six recalls, she was so astounded by their size she started measuring the bugs.
"I've kept that data," she says. "It's not a study. I was just curious. And I know the range they've been recorded at."
She's collected several lunker Rock Creek salmonflies measuring 49 millimeters, about two inches long from head to wingtip. Her goal each year is to catch a record - 50 millimeters or bigger.
At the UM School of Forestry, Six specializes in research in forest entomology and pathology - diseases of trees.
"I work equally with insects and fungi," she says. "My main focus is bark beetles. I'm more of a terrestrial entomologist than aquatic. Fishing forced me to learn about the aquatics."
The study of entomology is a natural extension of fly-fishing, Six says, that many anglers find fascinating. With her, however, it was the other way around.
"But I'm biased," she says. "I started fly-tying before I started fly-fishing, because I wanted to make bugs. I gave so many away
to friends."
Not surprisingly, Six has a special interest in tying ultra-realistic salmonfly imitations - both the nymph and adult versions - and imitations of other insects in the stonefly family.
Her nymph imitations, especially, are so realistic they look like they'll crawl off your hand. She makes two types - her "fishable" flies, and her "four-hour models" that are just for show.
"I just fish the rejects" of her show flies, Six says. "It's something about Murphy's law of fishing. The nice ones are the ones you lose in a tree."
Going fishing with Six on Rock Creek during the salmonfly hatch is a combination treasure hunt-natural history lesson.
"The hatches here are so incredible compared to where I came from (California)," says Six. "It's because the water's so clean. Salmonflies really require high quality, fast, clean, well-oxygenated water."
Like Rock Creek.
"I like Rock Creek a lot," she says. "It's about my favorite place. We'll see if we can find a trophy salmonfly today."
In Montana, she continues as we jounce along Rock Creek's rough, narrow, dusty road, most salmonfly hatches occur in June during spring runoff, keyed by a specific water temperature. Usually, the hatch gradually moves upstream over a period of days or weeks.
"The warmer it gets," Six says, "the faster the hatch gets over with."
Carolyn Persico at the Rock Creek Fisherman's Mercantile has tipped us off that the hatch is heavy about 20 miles upstream, around the Siria Campground and the Puyear Ranch.
"When they get ready to hatch," says Six, "the nymphs start migrating to the edges of the stream late in the afternoon and continue into dusk. When they're active, they're most likely to be dislodged, so that's the best time to fish the nymphs.
"The nymphs take three to four years to mature. So you have overlapping generations in the river and you can fish the nymphs all year long. Other types of nymphs are only available at certain times of the year. Long lives like that are unusual for any insects. It makes them pretty neat."
The nymphs, which can range from 25 to 50 millimeters, live mainly in large rivers or streams with loose, rocky bottoms and swift currents, Six explains. They crawl under rocks and woody debris to graze on algae, leaves and diatoms (one-celled organisms.)
"They're strictly vegetarians," she says. "Golden stones are just the opposite. They're predators. They eat other insects."
Salmonfly nymphs "clump together in congregations of the same size. Some places will have a bunch of big ones. Another place will have a bunch of little ones. And another place will have a bunch of middle-sized ones."
The nymphs climb out of the water onto streamside rocks and vegetation to hatch into winged adults, leaving behind a hollow husk of their nymph form.
Salmonfly adults are active during daylight hours, Six continues, as we scan the streaks of sunlight slanting through the trees above the creek for our first sighting of a salmonfly in flight.
"They tend to stay close to shore," she says. "Like most of the earth's organisms, it seems, salmonflies attract mates by making a spectacle of themselves. They rock back and forth and tap their abdomens on rocks or vegetation, producing a drumming sound. Prospective partners hear the drumming and respond by periodically drumming and crawling toward the other drummers. Finally, they find each other and mate."
We decide to stop the truck and take a closer look for bugs in the brush. Six soon spots an adult salmonfly clinging to the underside of a willow leaf, its long variegated gray wings folded flat over the segmented orange body.
"Aren't they beautiful?" she says.
She pulls out a small metal ruler and sets the bug on it.
"Thirty-five millimeters," she says. "You record the sizes."
Once we get used to peering into the maze of willow branches and leaves, our eyes begin to pick out the form and color of the bugs more quickly.
We stalk our quarry stealthily, slipping in and out of the stream in our waders, threading our way through the brush to surprise the bugs.
Six plucks them from their perches one by one and holds them on the ruler, before releasing them to flutter away like small helicopters, all the while continuing her natural history commentary.
"Thirty-seven millimeters," she says. "Thirty-eight - 40 - 37 - 37. Oh my god, that's a killer one - 47 millimeters. It works like fishing. You round up when you measure. That must have been a female. Females are bigger than the males.
"Thirty-five millimeters. The size depends on the food too. Some nymphs end up where there's better food habitat. Forty millimeters - 38 - 38. This is a golden stone. Wow, it's huge, as big as a salmonfly.
"Oh, looky here. There must have been some drumming going on in this bush. Forty-six millimeters. I'll straighten this one out, stretch it a little. Forty-eight millimeters. That's a trophy, but no record. Forty-four - 37 - 39. This is not a good bush. See this orange fluid. They have glands behind their legs that release it. It's a defensive secretion. It doesn't seem to keep the birds away though. They're a feast for the robins, western tanagers, kingbirds.
"We need another bush where they're mating. Thirty-seven millimeters - ah, a mating pair 47 and 43 - another 48. So close. Forty-five - 38. Here's another giant golden.
"Bugs are very cool, very under-appreciated, kind of like fungus. Bark beetles carry a kind of yeast on their bodies. We're not sure why. We believe it may provide a source of nutrition and vitamins. I separate it and culture it and make bread and beer with it. It makes really good India pale ale and stout. Fish apparently don't eat bark beetles though. I've tied some imitations and the fish didn't pay any attention to them.
"Sometimes, the earliest emergences of salmonflies are the largest. So, as we go upstream we should be running into an earlier emergence, and we might have a better chance of finding a record. Well, that's one strategy anyway."
We take a break from the bug hunting to take a few token casts in Rock Creek - "as long as we're here." We each hook and lose one fish. But the quest for a record salmonfly beckons us back to the brush.
"Oh, there goes a big one," exclaims Six. "Rats. That was a big one flying. I don't know where it went though."
Fifty millimeters ... at least, she estimates.
"That's the big one that got away," she says ruefully.
You'll know where to find her next June.
Reporter Daryl Gadbow can be reached at 523-5264 or at dgadbow@missoulian.com
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