Insect Classification

Last week I posted a brief commentary on Pteronarcys californica, a stonefly species found in Alberta. For those of you who are new to the world of fly fishing or entomology, this may be a good example with which to explain how scientists classify and name insects (along with other organisms). Knowing how the different species of insects are classified will help you to understand how the bugs that trout feed on are related to each other, and what to expect in terms of the physical appearance and general behavior of the different groups.

In the west, the stonefly Pteronarcys californica is most often referred to by its common name, the Salmonfly. Many other insects familiar to fly anglers also have common names that appear with great frequency in the fly fishing literature (e.g. Golden Stone, Pale Morning Dun, Blue Winged Olive, March Brown etc.). The problem with common names is that they are not always used in reference to the same species of insect. The term Salmonfly for example is sometimes broadly applied to any large dark stonefly species found on western trout streams; and in eastern Canada “Salmonfly” is sometimes used in reference to a completely unrelated species of mayfly. This can lead to confusion among anglers when discussing hatches, and which insect species are present on specific trout streams.  

To avoid this confusion the scientific community has adopted a standardized system for naming and classifying all living organisms. This system assigns a unique two-part name to each species (binomial nomenclature). The system also includes a hierarchical arrangement that organizes related organisms into various groups (taxa) based on characteristics that are common to members of each group. The groups start as general and broadly inclusive, and become more and more specific until the individual species level is reached. The classification hierarchy in our Salmonfly example would look like this:

Kingdom – Animalia

     Phylum – Arthropoda

          Class – Insecta

               Order – Plecoptera

                    Family – Pteronarcyidae

                         Genus – Pteronarcys

                              Species – Pteronarcys californica

The broadest group is the Kingdom level – if you are an animal (i.e. not a plant or bacteria), you are included at this level under the moniker Animalia. The next level divides all animals into various Phyla (singular = Phylum). Many of the aquatic invertebrates that trout feed on (including our stonefly example) are in the Phylum Arthropoda – this includes animals with hard exoskeletons and jointed legs (e.g. crayfish, shrimp, crabs, insects, zooplankton etc.). Following this, we have the Class level where most arthropods with 3 pairs of jointed legs are placed in the Class Insecta (Insects). From here (at the Order level) some of the names should begin to sound familiar to most fly anglers: The Order Plecoptera includes all Stoneflies, Ephemeroptera would be Mayflies, Trichoptera are the Caddisflies, etc.

As we proceed to the Family level, the members of each group are becoming more closely related to each other from an evolutionary perspective. Once we get to the Genus level, the individual species within each genus are so closely related that they often look the same, share similar habitats, and exhibit similar behaviors – often requiring expert knowledge and a microscope to tell one species from another. There are other levels within the hierarchy but for simplicity I have left some out (e.g. Subclass, Infraorder, Subfamily etc.).

Down at the species level each binomial species name includes the genus name (always capitalized and in italics) followed by the species epithet (all lower case and italicized). The same binomial species name is used by scientists worldwide whenever referring to the same bug (i.e. everyone speaks the same language). Once the full species name has been used in a written article, the genus name is often abbreviated for brevity (e.g. Pteronarcys californica becomes P. californica).

Rhyacophila sp. - A Caddisfly larva in the Order Trichoptera
When the species of a specimen is unknown, it is written as the Genus name followed by "sp."

For many anglers just knowing that an insect they have seen streamside is a stonefly, mayfly, caddisfly, or something else entirely may be as in depth as they wish to go; just tie on a fly of the same general shape, size and color as the natural and start fishing. But for others, part of the enjoyment of the sport lies in knowing the details – knowing why trout are feeding on this bug and not that one, why some insects emerge mid-stream while other crawl out on the bank, and why one style of fly is more effective than another at certain times. Fly fishing at this level is about being observant; putting the various pieces of the puzzle together to form a hypothesis about what the trout are feeding on, then testing that hypothesis, and refining the approach as necessary. This requires knowledge of at least what Family or Genus the bugs that are hatching belong to.

It Won't Be Long Now

For those of you who like to start the season early by poking around in some of the spring creeks that have open water (and are in open season), a few hatches should start to trickle off over the next week or so – assuming of course we continue to get some warm days more than a few degrees above zero. Winter stoneflies (Capniidae) will be the first to show up and will begin to emerge on any stream that has pockets of open water. You will not likely see fish rising though since these bugs emerge by crawling out – and do not stimulate surface feeding activity until enough adults return to the water to lay eggs.

Utacapnia trava (Capniidae) is usually one of the first winter stonefly species to emerge on Stauffer Creek. Note that only the females have fully developed wings; the darker male seen on top, although it looks like a nymph, is actually a sexually mature adult with short stubby (bracypterous) wings.  A small (#16-18) nymph tied sparsely using black rabbit or muskrat fur will usually do the trick.

The fish will still be quite sluggish at this time of year and will not move far to take a fly, so if you are drifting nymphs, you will need a slow presentation that positions the fly within inches of their nose. The low clear water will also require the utmost patience in your approach and the most delicate presentation you can muster; but when everything comes together, the reward of hooking a fish in winter is well worth the effort.

Pteronarcys californica in Alberta?

I responded to an e-mail from a local fly angler the other day regarding the presence of the stonefly species Pteronarcys californica (aka the Salmonfly) in Alberta. Apparently there is some debate among Alberta fly anglers as to whether or not this species is actually present in the province, and if the many Salmonfly hatches observed by anglers on their local trout streams are indeed P. californica.  

There are relatively few records in the scientific literature for P. californica in Alberta. Most of these references are from studies done on the Crowsnest River in Southern Alberta (see for example Townsend and Pritchard, 2001). The paucity of official scientific records for this and other aquatic insect species can be attributed to the lack of province wide sampling required to fully understand the full distribution of most aquatic invertebrates in Alberta. I have personally collected mature P. californica nymphs from Prairie Creek and the lower end of the Clearwater River near Rocky Mountain House. So the short answer to the first question is yes, P. californica is definitely present in Alberta.

Local authors have also written about the legendary Salmonfly hatches on several Alberta trout streams. Of course the P. californica hatch on the Crowsnest River is the most well-known but hatches have also been documented on Prairie Creek, Clearwater River, and the Red Deer River. We also know that P. californica is common on the pacific side of the Rockies, and in streams and rivers on both sides of the Rockies south of the border. In Alberta they are found only in sporadic pockets along the east slopes of the Rockies.

Pteronarcys californica nymph from the Clearwater River

So what about all of the other purported sightings of Salmonflies that have been discussed on local fly fishing forums?

See for example: http://forum.nlft.org/index.php?showtopic=3484&mode=threaded&pid=22939

I think much of the confusion comes from anglers erroneously assigning the term Salmonfly to any large dark colored fluttering bug they see streamside. There are several stonefly species in Alberta (not to mention other insect orders) that come close to the size of P. californica, making the potential for misidentification significant. Without considerable experience, a good close look, and sometimes an actual specimen in hand (or under the microscope), these sightings are just not reliable. To further complicate matters, both the adults and nymphs of Pteronarcys californica are easily confused with Pteronarcys dorsata, another more widespread stonefly species found in Alberta. P. californica and P. dorsata are quite similar in appearance, have similar life history and habitat requirements, and sometimes coexist in the same stream. In short, unless you are on a stream known to harbor a population of Salmonflies, any large dark stonefly that you see is unlikely to be P. californica – the only way to be sure would be to collect a specimen and have it identified by an experienced entomologist.

References:

Townsend, G.D. and G. Pritchard (2001). A comparison of methods for analysis of a long aquatic insect life history: Pteronarcys californica (Plecoptera) in the Crowsnest River, Alberta. In: Trends in Research in Ephemeroptera and Plecoptera. Ed. E. Dominguez. Kluwer Academic/Plenum Press, pp. 251-258.

Rod Build Update and Summary

I was out this weekend continuing with my quest for wood fly rod blanks. I have still not found anything better than the first blank I cut a few weeks back but I did locate a potential future candidate. Like the blank I have already harvested this one is close to 9 feet tall, has a minimal number of small branches and knots, and is almost perfectly straight – the only flaw is that it is a little on the skinny side. Most flaws usually result in a complete rejection of the blank but because this one is perfect in every way except the thickness, it is worth keeping an eye on. The plan is to monitor it for a few years and cut it when the base reaches about 3/4” to 7/8” in diameter. It found this one growing in the middle of a tight cluster of taller trees. To help it out a little, and to increase its potential as a fly rod blank, I carefully trimmed off all of the small lower branches so that they do not develop into larger knots. I also thinned out the cluster a little so the sapling has a little more room to grow. This one will be a long term investment but will be well worth the effort.

I thought it may be worthwhile here to including a summary of the steps involved in the overall rod construction process for those of you who are considering building your own;

1.      Selecting the blank (as long as it takes to find a good one)

2.      Cutting and drying the blank (1-2 hour set-up but requires a full year to complete)

3.      Shaving off the bark and initial sanding (2-3 hours)

4.      Heat treating the blank (2-3 hours)

5.      Sanding to desired taper (up to 16 hours)

6.      Pseudo-lamination process (1-2 hour set-up but requires about 6 months to complete)

7.      Sanding to final taper and varnishing the blank (4-6 hours)

8.      Assembling the grip and reel seat (2-3 hours)

9.      Attaching rod guides and varnishing the threads (3-4 hours)

10.   Building a storage tube (1 hour)