Entomology – Linecasters

South African stonefly nymph imitations

By Fred Steynberg and Mario Du Preez

May flies, and to a lesser extent caddis flies, have over the years dominated the attention of fly dressers in South Africa – maybe sometimes disproportionately so. Stomach pumping exercises performed on trout caught inhabiting the fast flowing waters of the North Eastern Cape, as well as regular seine netting, have confirmed, at least in the minds of the authors, the importance of stoneflies in the diet of trout in these river systems. Dave Whitlock (see Guide to Aquatic Trout Foods) , for example, argues that the “… stonefly’s life cycle, habitat, and size make it highly compatible to fly-fishing and fly-tying … maybe even more so than the mayfly.” Careful scrutiny of local literature on fly tying has, however, revealed a paucity of South Africa-specific stonefly nymph imitations. This article presents a short overview of the stonefly life cycle, the stonefly nymph anatomy, the most important families of stoneflies found in South Africa, and a description of the materials required and tying procedure for an impressionistic, South Africa-specific, stonefly nymph imitation.

The Latin name for the stonefly is Plecoptera. The latter is broken up into pleco, which means “folded”, and ptera, which means “wings”. The “folded wings”-description refers to a unique physical characteristic present during the adult stage in the stonefly’s life cycle.(i.e. there is no pupal stage), and consists of three distinct phases, namely the egg stage, the nymph stage, and the adult stage. Unlike mayflies, stoneflies hatch all year-round. Hatching, however, occurs mostly during the night, and as such adult stoneflies and their imitations are of little importance to the fly fisherman in South Africa.

Stonefly nymphs live on the sides and undersides of stream-bottom structures, such as boulders, stones and plant detritus, in swift-flowing mountain and coastal streams and rivers. Stoneflies require unpolluted and swift flowing water with high oxygen content, and for this reason they are often used as an indicator of the relative water quality of a stream or river. Their conspicuous absence from a fast flowing stream or river is a strong indicator of compromised water quality. Stoneflies are seldom, if ever, found in stationary water (i.e. dams or other water impoundments) or very slow moving water – the reason for this absence is the limited level of adaptation of the stonefly’s breathing apparatus to changing water conditions.

Due to their limited ability to adapt to varying habitats in comparison to, for example, mayfly nymphs, the nymphs of the different families of stonefly show marginal variation in shape. This almost uniformity in shape across different families makes it easy to distinguish between a mayfly nymph and stonefly nymph. More specifically, the stonefly nymph exhibits the following physical characteristics: The body consists of 1) a head with two long antennae, 2) a clearly segmented thorax with three legs on each side, two well-defined wing pads on top and feathery gills situated on the bottom and between the six legs, 3) and an abdomen consisting of ten clearly defined segments, and two well defined tails on the final segment – gills are also found between the two tails.

Stonefly nymphs are easily confused with mayfly nymphs. The former, however, have large, feathery gills under the thorax and between their legs, whereas the gills of the mayfly are situated on the segments comprising the abdomen. Stonefly nymphs have two sets of wing pads compared to the mayfly nymph, which has one set only. Moreover, stoneflies have two tails instead of the three found on most mayflies.

The two Stonefly families found in South African waters are the Perlidae family and the Notonemouridae family. The large and robust body of the nymphs of the Perlidae family is approximately 20 to 25mm long, with black and yellow or dark brown on their backs. The upper body is clearly segmented and the two antennae on the head and the two tails on the last segment of the abdomen are highly visible. The photograph below shows a Perlidae stonefly nymph.

The nymphs of the Notonemouridae family, on the other hand, are small with a body length of between 5 and 8 mm. The body colour of these nymphs is generally a dull grey or brown.

The two stonefly nymph imitations shown in the photograph above are fairly similar, the one tied in a realistic manner and the other impressionistic. They require the following materials:

Realistic Pattern:

Hook: curved stonefly hook # 14 to 8
Weight: 10 to 15 turns of 0.015 mm lead wire
Tail and antennae: X2 Cane rat skin fibres
Abdomen: Golden rabbit dubbing or similar
Back: Clear thin-skin back
Ribbing: 4X monofilament
Thorax: Golden rabbit dubbing
Wing case: Light brown thin-skin mottled with black or dark brown marker pen
Legs: Ring neck pheasant tail fibres

Impressionistic Pattern:

Hook: curved stonefly hook #14 to 8, or long shank nymph hook
Weight: 10 to 15 turns of 0.015 mm lead wire
Tail and antennae: X2 Cane rat skin fibres
Abdomen: Golden rabbit dubbing or similar
Back: N/A
Ribbing: Ultra wire copper
Thorax: Golden rabbit dubbing
Wing case: Golden pheasant tail fibres or mottled turkey fibres
Legs: Brush out dubbing with dubbing brush

These imitations should be fished in the cushioned boundary layer just above the stream bottom. Furthermore, both patterns are best fished in a drag free drift. The realistic pattern should work well in medium clear water current and the impressionistic pattern will suffice in fast currents where fish have little time examining the fly.

South African stonefly nymph imitationsKosie2022-10-21T11:17:45+00:00

Spiders for Survival

By Fred Steynberg

Trout, whether alien in our waters or not, have over the past hundred years become an integrated part of our fresh water systems and millions of rand is poured into our country each year because their attraction to fly fishers. Fly fishing for trout is the cradle of fly fishing and it is surrounded by mysticism and history. It is said that fly fishing is one of the most written about sports or past-times ever and it surely has become the most popular ‘el fresco’ style recreation for a wide range of age groups. Trout is also on the top of the serious fly fishers list of fish to target on fly and rightly so. The reason for this is that one can never fully predict in what way a wild trout will react from one minute to the next, leaving us constantly challenged by them. We will interminably keep improving our skills and equipment to close the gap between us and these amazing creatures.

Trout have many different food sources at their disposal but these are often small and they need to consume a large amount to be able to grow and survive. In our waters they also do not have the luxury of mega hatches such as those found at specific times in other trout inhabited countries, where they gorge themselves on the abundance. Trout in our country have to become opportunistic and feed on a wide variety of terrestrial and aquatic food sources. Spiders, although rare are one of them and as distasteful as it might sound to us as humans, trout only see them as a vulnerable, soft and available morsel. Spiders are not as plentiful as say for example mayflies, midges or caddisflies, but when they are swept away by currents after landing up in the water, will be taken as food. The stomach contents of trout have revealed signs of sporadic spider catches.

Spider patterns work especially well, if tied and fished correctly to sighted trout in clear mountain streams. These patterns should be fished up steam on floating lines with long, thin leader and tippet configurations. Spiders that fall into the water from streamside vegetation do not swim out of a current, but will usually wait until pushed onto some vegetation before climbing out of the water. Aquatic spiders run across the water in quick, fast concessions. I have found that the best technique to imitate spiders in general is to gently place the imitation a meter or two ahead of the feeding trout. The trout should recognize the imitation as a food source and gently sip it off the surface. I have often been amazed how gently spider patterns are eaten and the reason for this can only be that the trout understand that the spider is in a vulnerable position.

Some species of spiders that live and feed on the surface of the water are quick, extremely buoyant and agile and not as vulnerable as others. Even if incidentally bushed beneath the surface by turbulent water, large rain drops… they always trap an air bubble onto there body that pop’s them back up to the surface. Some even use an underwater swimming action to maneuver themselves into favorable positions.

Spider patterns that float beneath the surface should also produce fish, but the visual aspect of fish a floating spider excites me. This way of presenting a pattern to visual fish will also immediately show whether the fish reacts to the offering or not. If the sighted fish does not move to a well presented spider imitation then the pattern may not have the correct…or the fish is rather tuned into some other food source that is of abundant.

Sighted fish in clear water will however more often be alarmed by bad presentations or long casts that ultimately line the fish.

To build a buoyant spider pattern that will be recognize as a spider by trout I use a soft foam spider body that can be cut from closed sell foam or bought in pre cut shape.

The foam body is tied on a # 16 or 14 thin wire caddis/sedge hook. To ad to the visibility of the fly a white or brightly colored post is tied in. The post can be of any buoyant, high vise material but egg yarn, poly yarn or packaging foam will probably work best. The thorax of the spider is lightly dubbed black or brown CDC dubbing to add to the floatability of the fly and often the CDC traps air bubbles making it look like the real thing. A black or dark dun cock hackle, ‘under hackle’, is firstly tied in around the post. This hackle should be sparse, 2 wraps, and the fibers just longer than the gape of the hook.

The legs are mottled brown partridge hackle sparsely wrapped around the base of post and it is necessary to have the tips of the hackle pointing down. The legs can be short but I prefer legs that stick out 15 – 20mm from the post. It is a good idea to pre-tread the hackle/legs of the spider pattern with Hydro-stop after the fly is tied as this should keep the fibers from soaking in water for a longer period of time.

Much has been written about the diets of trout, the way that they feed on specific food sources and when they feed on them. Wild trout can be extremely selective and often, during May or Caddis fly hatches, refuse any imitation but the one that fully represents the specific food source in shape, color, size and movement. This can frustrate angler’s immensely but never fails to bring back the angler that wants to present the right fly at the correct time. For many it is about catching the fish and the method is of lesser importance but for others, maybe purists, fly fishing is an art that thrives on patience, persistence and dedication.

This foam body spider pattern is a generic pattern that works amazingly well if presented correctly. For all intentional purposes specific spiders and there scientific names have not been mentioned as the generic pattern would rather simulate a range of different spider species. I find it useful to always have a couple of spider patterns in my fly box for a specific occasion when I do find a large fish looking around for something to eat in clear Mountain streams.

Spiders for SurvivalKosie2022-10-21T11:22:53+00:00

A South African damselfly nymph imitation

By Fred Steynberg and Mario Du Preez

Due to the fact that damselflies inhabit the slow-moving or still water areas of rivers, most fly fisherman, especially those who practice upstream nymphing in fast flowing water, pay scant regard to their prevalence and their importance in the diet of trout. Inspection of aquatic vegetation and submerged tree detritus, found mainly on the edges of the slow moving sections of rivers and streams, as well as stomach pumping exercises performed on trout, however, confirm the status of damselflies as an important food source for trout in rivers and streams. This article presents a short overview of the damselfly life cycle, the damselfly nymph anatomy, the most important families of damselflies found in South Africa, and a description of the materials required and tying procedure for an impressionistic, South Africa-specific, damselfly nymph imitation.

Damselflies (Zygoptera) and true dragonflies (Anisoptera) comprise the suborders of the order Odonata. The Latin name for the damselfly is broken up into zygo, which means “yoked”, and ptera, which means “wings”. The “yoked wings”-description refers to a unique physical characteristic – the wings of the damselfly are more yoked than any of the other aquatic invertebrates trout feed on.

The life cycle of the damselfly is incomplete and consists of three phases of development, namely: the egg stage, nymph stage and the adult stage (the newly emerged adult is known as a teneral). The damselfly nymph has a life span of one to two years depending on the specific species, and, as mentioned above, occupies the aquatic vegetation found in the slow or still water areas on the edges of rivers. The nymphs swim amongst the aquatic vegetation by moving their abdomens in a side-to-side or wiggling fashion, or simply walk around amongst the aquatic vegetation. Damselfly nymphs are efficient predators that actively feed on smaller aquatic invertebrates – to this end their lower lips (also referred to as masks) are modified, which allows them to fold open to catch prey. Closer inspection of the damselfly nymph shows that the lower lip lies tucked back under its head.

Prior to emergence the damselfly nymph swims or crawls to aquatic vegetation or other in situ structures, which break the water’s surface, and crawls up to the surface, where it emerges into the adult. Trout readily target the nymph during this period of migration – due to the fact that these nymphs are relatively large when compared to mayfly, caddisfly and stonefly nymphs, large trout will commonly feed when they are emerging. Damselfly nymphs may on occasion loose their grip or footing and as a result get washed downstream, especially during floods – this occurrence is known as “catastrophic drift”.

The common physical characteristics that define the anatomy of all damselfly nymphs include: two to three tracheary gills (erroneously referred to by some as tails) situated at the end of the abdomen; an abdomen long and slender in appearance; a very short thorax (broader than the abdomen); dorsal wing cases overlapping the upper thorax and abdomen; three sets of long, spider-like legs situated along the thorax; and a short head, wider than the thorax, on which a large pair of compound eyes are located. All the South African families have visible antennae situated on the front part of the head.

Dragonfly nymphs are easily confused with damselfly nymphs. It is, however, fairly easy to distinguish between the dragonfly nymph and the damselfly nymph – dragonfly nymphs are generally stockier in appearance compared to damselfly nymphs (damselfly nymphs have thin, cylindrical bodies), and the dragonfly nymphs do not have tracheal gills situated at the back of their abdomens, whereas the damselfly nymphs do.

There are seven families of damselfly found in South Africa rivers and streams namely, Calopterygidae, Chlorocyphidae, Chlorolestidae, Coenagrionidae, Lestidae, Platycnemidae, and Protonearidae. Of the aforementioned families, the Coenagrionidae family is found most often, during seine netting exercises performed in the rivers and streams of the North Eastern Cape, as well as the stomach contents of trout, subjected to stomach pumping, that inhabit these rivers and streams. This family exhibits a body colour ranging from pale green to pale brown.

Although there are seven different families of damselfly that occupy South African rivers and streams, one only requires a single, generic imitation in either green or brown. The creation of an artificial facsimile of every single family, whilst at the fly tying bench, translates into superfluous time wasting – time better spent fishing than fly tying.

The damselfly nymph imitation shown in the photograph above is neither suggestive nor exact, but is impressionistic, and requires the following materials:

Imitation 1.

Hook: # 12-8, 2 X long nymph hook.
Eyes: 30-40 lbs mono.
Weight: 6-12 turns of 0.015 mm lead wire, depending on flow and depth.
Tail/ Gills: Olive, brown or tan marabou
Abdomen: Olive, brown or tan rabbit or squirrel dubbing
Wing case: thin-skin, scud back or in this case 1mm olive or brown foam, pulled tight.
Ribbing: 6-10 lbs mono filament
Thorax: Olive, brown or tan squirrel or rabbit dubbing
Legs: Thin, flexible round rubber

Imitation 2.

All the same except for abdomen that consist of green, olive or tan nymph rib.

The imitation should be fished in slow water conditions with a slow hand-twist retrieve or dead drift in faster water conditions.

A South African damselfly nymph imitationKosie2022-10-21T11:29:33+00:00

A South African dragonfly nymph imitation

By Fred Steynberg and Mario Du Preez

Dragonflies differ from most other aquatic invertebrates in two important respects: first, they usually have a much longer life span, and, second, they are normally much larger in size (during similar phases of development). These characteristics, coupled with the fact that dragonfly nymphs are very vigorous predators, enhance their levels of exposure, as well as appeal, to yellowfish and trout. The abovementioned differences between dragonfly nymphs and other aquatic insects, as well as stomach pumping exercises carried out on trout caught by the authors, verify the status of dragonfly nymphs as a major target for, especially, cruising trout and yellowfish in rivers and streams. This article presents a short overview of the dragonfly life cycle, the dragonfly nymph anatomy, the most important families of dragonflies found in South Africa, and a description of the materials required and tying procedures for impressionistic, South Africa-specific, dragonfly nymph imitations.

The true dragonflies (Anisoptera) and damselflies (Zygoptera) comprise the suborders of the order Odonata. The Latin name for the dragonfly is broken up into aniso, which means “asymmetrical”, and ptera, which means “wings”. The “asymmetrical-wings”-description refers to a distinct anatomical feature – the discrepancy in size between the insect’s fore and -hind wings – the forewings are narrow and the hind wings are wide.

Not unlike the damselfly, the dragonfly has an incomplete life cycle, which consists of three stages, namely the egg stage, nymph stage and the adult stage. The life span of the dragonfly nymph, its water breathing stage, varies in duration, and can be anything from two to four years depending on the specific species. Dragonfly nymphs occupy a habitat which could include aquatic vegetation, stones and rubble, or submerged tree stumps and branches. In comparison to mayflies, caddisflies, stoneflies and midges, these insects are not found in vast concentrations in the specific areas they inhabit.

A dragonfly nymph moves by means of a very unique mechanism – it takes water into its system via an anal breathing and propulsion valve (situated at the end of the abdomen) and ejects the water out quickly, which propels the insect forward in short bursts. Dragonfly nymph movement is not restricted to sudden darts, but also includes crawling. As was mentioned above, dragonfly nymphs are effective and active predators that feed on any smaller aquatic invertebrates as well as small fish. The lower lips, also called ‘masks’, of the dragonfly nymph are modified to allow them to fold open to catch prey. As with the damselfly nymph, closer inspection of the dragonfly nymph reveals a lower lip that lays tucked back under its head. As adults, dragonflies hunt on wing in a hawk-like fashion or they wait in ambush to attack passing prey that includes a range of insects smaller than themselves.

Adult dragonflies are able to fly up, down, forward and backwards in quick bursts and according to Warick & Michele Tarboton’s handbook “A field guide to the Dragonflies of South Africa” they can reach speeds of up to 70km/h.

The mature dragonfly nymph crawls out and up on aquatic vegetation or other structures next to the stream bank, where it emerges into the adult. During their migration to the shoreline trout do target them, although the number of migrating dragonfly nymphs is small in comparison to that of migrating damselfly nymphs.

The common physical characteristics that define the anatomy of all dragonfly nymphs include: an abdomen thick and triangular in appearance; a very short thorax (narrower than the abdomen); a short head on which a large pair of compound eyes (almost touching each other) and two front facing, short antennae are located; wing pads overlapping the upper thorax and abdomen; and three pairs of legs situated along the thorax.

Although dragonflies and damselflies form part of the same order of insects, they do exhibit fairly different body profiles. Damselfly nymphs have thin, cylindrical bodies whereas the bodies of dragonfly nymphs are generally stockier in appearance. Moreover, dragonfly nymphs do not have any gills situated on the outer surfaces of their bodies, whereas the damselfly nymphs do (the tracheal gills situated at the end of the abdomen).

There are four families of dragonfly found in South African rivers and streams namely, Aeshnidae, Gomphidae, Corduliidae and Libellulidae. Of the aforementioned families, the Aeshnidae and Gomphidae families are found most often, during seine netting exercises performed in the rivers and streams of the North Eastern Cape. The Aeshnidae (‘swimmers’) family exhibits a body colour ranging from green, brown to black. This family of dragonfly has a very distinctive body shape compared to the other families found in rivers and streams: the body is longer with a very definitive taper.

The Gomphidae (‘burrowers’) family of dragonfly is brown coloured and their body profile is shorter and more oval in appearance compared to that of the Aeshnidae family. The Corduliidae and Libellulidae (‘crawlers’) families also exhibit body shapes that are short and oval and their bodies are also mainly brown in colour, and as such, are easily confused with the Gomphidae family. The relative similarity among the body shapes and colouring of the Gomphidae, Corduliidae and Libellulidae families allows the fly tier a measure of leeway: he or she only has to tie one generic pattern which emphasizes the abovementioned similarities or trigger points.

We have, however, included three imitations below, which covers swimmers, burrowers and crawlers.

The dragonfly nymph imitations shown in the photograph above are neither suggestive nor exact, but are impressionistic, and require the following materials:

Aeshnidae (swimmer) imitation:

Fish deep in still waters and use a fast or slow hand twist retieve with intervals. Fish in rivers and streams using a Leisenring lift in slow pools or drag free in currents.

Hook: # 12-6 2-3X long nymph or streamer hook
Weight: Optional
Eyes: 80-100 lbs burend mono fillament
Abdomen: Black, brown or olive chinelle or wool under body dubbed over
Tail: Black, brown or olive marabou (optional)
Thorax: Black, brown, olive Squirrel dubbing with seals fur mix
Wing case: Swiss straw or rafia
Legs: Brushed out seals fur or rubber legs or thin round rubber

Gomphidae(burrower) imitation:

Fish deep or as close as possible to the bottom in freestone rivers.

Hook: # 12-10 2X long nymph hook
Weight: Lead wire
Eyes: 80-100 lbs burned monofilament
Abdomen: Olive or light brown chenelle
Tail: Marabou (optional)
Thorax: Squirrel dubbing with seals fur
Wing case: Rafia or Swiss straw
Legs: Brushed out seals fur

Corduliidae and Libellulidae imitations (crawler)

Fish very slowly over weed beds in still waters (the deer hair helps keep the fly boyant).

Hook: #12-8 nymph hook
Weight: none
Eyes: 80-100lbs monofilament burned
Abdomen: Brown or olive spun deer hair
Tail: Marabou
Thorax: Squirrel dubbing
Wing case: Raffia or Swiss straw
Legs: Mottled rubber

Fishing method

Dragonfly nymphs spend 99 % of their time crawling around on the river or still water bottom or on some form of water plant or structure in the water. The crawling movement is very slow and because it is on a structure, it is hard to imitate as the fly snags especially if a weed-guard is not incorporated. It is only when fleeing from danger or when attacking prey that the nymphs generally move by ‘jet propelling’ themselves. This quick darting action can be imitated in slow deep pools or in still waters by using a quick hand-twist retrieve interspersed with intervals, which allows for the simulation of rest periods, and/or for the fly to achieve depth before resuming the action. This method attracts fish or triggers a reaction, but often a very slow retrieve,which hardly moves the fly, or a dead drift in slow moving water or in water where currents are absent, works just as well and attracts the interest of, especially, larger fish that are looking for a vulnerable, big morsel such as this. A method that is often successful in slow, deep pools in streams when using these imitations is the ‘Lisering lift. The lift would resemble a fleeing nymph and often trigger fish. A long leader is essential and no strike indicator is used.

One of the most effective methods in stronger currents or in flowing water is still just casting it upstream and drifting it down with the current, drag free. This resembles a nymph that has lost its footing in the current and is now drifting down until it reaches a spot were the current in not too strong to fight.

These patterns are suggested imitations and work well if fished correctly. There are, however, many other effective imitations that could be copied or bought.

A South African dragonfly nymph imitationadministrator2022-10-21T11:27:23+00:00

Days that ants fly

By Fred Steynberg

This November, while guiding a couple of guys on highland mountain streams in Southern Africa, we came across a flying ant fall, this changed the course of the days fishing dramatically. We had begun fishing around 9 in the morning and because the water was high and the skies were slightly overcast and no fish were feeding off the surface we started prospecting with nymphs. Nymphing is often the only real successful or productive method to target fish that feed off an abundant living drift, (living drift is the down-stream drift of invertebrates that for some reason, have lost their hold on the river bottom and are swept down the current to ultimately become fish food.) In fact nymphing can be so productive that even the most well ‘fed’ fish in a natural stream will not refuse an imitation when fished correctly. This day seemed no different from any other and we caught numerous Rainbow trout and a half a dozen large smallmouth yellow fish on nymphs.

By lunchtime most of the cloud cover had burnt off and a slight downstream wind developed. Fish started rising on the odd occasion but we could not make out what they were feeding on as no insects were coming off or floating on the water surface (or so it appeared). I changed my clients’ nymph set-ups to dry fly rigs and we caught and missed a couple of the rising fish on terrestrial patterns such as floating spiders. What we did not realize was that a flying ant fall was happening a couple of hundred meters upstream in the direction that we were fishing. A few ants (that were hard to see on the water surface) had already started drifting down and this is what the fish were occasionally feeding on. As we fished up-river the rises became more intense and the fish rising, larger. We stared seeing mating flying ants in small clouds above us.

The queen ants were large, black and dark brown bodied with enlarged shiny abdomens while the males were less than half their size, blacker in colour and a lot slimmer. Some of the ants had fallen on the water whilst still attached in mating mode, making the meal for nearby fish even more irresistible. I tied on a larger black floating, flying ant imitation on relatively long tapered leaders attached to 4X tippet. The 4X tippet may sound like a slight over-kill but the fish were big, strong and were too frenzied to be tippet shy.

Left: the slimmer male ant. Right: larger queen ant

The nature of the smaller trout was to lie in one spot waiting for the ants to drift onto them while the Yellow fish and larger trout would swim around in larger pools frantically gulping up the ants. The yellow fish would often turn short of the ant, creating a splash with their tails as they turn, so close to the ant that it would ‘drown’. The yellow would swiftly return to collect the now, sub-surface meal. The moving fish can make life difficult, under these circumstances, for an angler who may struggle to accurately present flies, but patience is rewarded.

We found a healthy wild trout of about 20’’ cruising off the current, feeding wildly. One of the guys with me presented a flying ant imitation that fell well behind the fish. The fish continued feeding away from the fly and after a couple of gulps disappeared. The presented fly was still drifting on the surface when the angler turned to me asking if we had spooked the fish. At that moment, as Murphy would have it, the trout reappeared on the surface, gently sipping the imitation off the top. I shouted ‘yes’ as the fish disappeared and the angler instinctively struck, fortunately setting the hook. Two lessons can be learned from this: 1. Never take your eye off the dry fly or strike indicator that drifts on the water and 2. When there are flying ants on the water surface fish don’t often stick to lies or their usual patterns.

As the fish felt the hook and line tension it dove straight down into the natural water grass of the deep pool and imbedded itself. The angler had no choice but to swim in after it, not touching ground but eventually managed to free the fish and continue the fight.

Left: a wet angler with the good size wild trout, Right: fly in the vice

A couple of pools further upstream and a number of fish later we found a yellow fish female in a riffle lazily sipping ants off the surface. She was quite large but had no other apparent competition. It was amazing to witness such a large fish methodically feeding of the surface. Unfortunately we spooked some Yellows from the pool below the riffle and they shot up-stream alerting the big fish, pity because she would have been special on a dry fly.

Some flying ant info:

Flying ants or ants that fly and land up on the surface of the water are like manna from heaven to both indigenous Yellow fish and trout. This phenomenon which we anglers call an ‘ant-fall’ is seldom witnessed as it does not happen often. When however it does happen, fish will greedily react to the fall and will be on high alert, often lying close to the water surface to sip up the protein source that helplessly float down-stream.

Most ant species fly and the bigger the ant the more spectacular the reaction to the fall. Predatory birds are often attracted to the feast and are a tell tale sign of the event. The ant colonies do not communicate the flight but simply react specifically to temperature, humidity and wind speed.

Queen ants emerge from their nests and begin their nuptial flight with the smaller males in pursuit. Some queen ant will fly long distances but others only a couple of meters from the nest. They mate in the air after which they fall to the ground and lose their wings and attempt to start a new colony.

The flight is called the nuptial flight and many colonies of the same species can turn to flight simultaneously to minimize the effectiveness of predation. This collective flight between many colonies of the same species will ensure that new colonies are formed and that old colonies have an injection of new blood ensuring its survival.

Many of the ants from both genders land up in the water, especially when losing focus during the mating process. Flying ants are bad swimmers and once their wings get sucked onto the water surface they are doomed as the insect is too weak to lift them out. I have often rescued individual ants from the water surface, for inspection, and as soon as they dry and become mobile they fly away. Flying ant imitations have been around for ages and have saved many a day on the waters. Fish that are rising to floating ants will often not react to any other offering. This can be frustrating to the ill prepared fisherman.

I always carry a handful of floating ant patterns in different shapes and sizes, with and without wings. Travelling without flying ant patterns in your fly box is like going on a fishing trip with a medical kit that has no Imodium, you don’t often need them but if you do then you need it bad!

I have witnessed a dozen or more ant-falls in my life that have been close enough to the river to cause the ants to land up helplessly on the water surface. The larger fish in that specific river often awaken from their steady side-to-side nymphing mode and move into the upper water column to intercept the ants.

Once many years ago, four or five large fish fed so frantically on flying ants off the surface that from a distance they appeared to be otters rolling and playing on the water surface. Only when I moved closer could I make out the large trout feeding on the flying ants and what an amazing sight!

Left: a colourful Smallmouth Yellow from a riffle, Right: this 16’’ rainbow (cannibal) ate a 8’’ juvenile trout. The tail of the prey is still protruding from the predators mouth as the food source, partly decayed, was to large to swallow. This fish still accepted a # 14 bead-head hare and copper nymph

Nymphing down stream

Days that ants flyadministrator2022-10-21T11:26:54+00:00

South African Leptophlebiidae (prongills) nymphs

By Fred Steynberg and Mario Du Preez

Izaak Walton, in his classic work entitled ‘The Compleat Angler’ published in 1653, wrote the following about the trout’s favourite prey: “… and he especially loves the May-flie,” Many years later, Dave Whitlock (see ‘Guide to Aquatic Trout Foods’) unequivocally reaffirms the status of the mayfly by remarking that “Mayflies are the best known and most popular of all trout foods”. Gary Borger, in his mammoth work entitled “Presentation”, also describes mayflies as “…the insect group upon which modern fly fishing was founded.” Stomach pumping exercises, performed on trout caught inhabiting the rivers and streams of the North Eastern Cape, lend further credence to the astute observations of Walton, Whitlock and Borger. More specifically, the results of stomach content analyses, performed over more than 10 years by the authors, reveal that mayflies constitute, on average, in excess of 75% of the food forms found.

The Latin name for the mayfly order is Ephemeroptera and describes two things synonymous with the mayfly: the adult stage in the mayfly’s life cycle is short-lived (usually between one and two days in duration) and the adult is a winged insect. There are nine families of mayfly found in rivers and streams in South Africa. These include the Baetidae, Caenidae, Heptageniidae, Leptophlebiidae, Oligoneuridae, Teloganodidae, Tricorythidae, Polymitarcyidae, and Prosopistomatidae families. Of the abovementioned families, only the first seven are of importance to trout, and hence, the fly fisherman. The last two families, due to their behaviour and habitat choice, are seldom, if ever, targeted by trout during their nymphal phase of development.

This article presents a short overview of the Leptophlebiidae family’s life cycle, the Leptophlebiidae nymph anatomy, the Leptophlebiidae sub-adult (dun) anatomy and descriptions of the materials required and tying procedures for impressionistic, South Africa-specific, Leptophlebiidae nymph and sub-adult imitations. The Leptophlebiidae mayfly family is also sometimes collectively referred to as “prongills” and there are twenty known species in South Africa. The most famous species of this family mentioned in international literature include the claret dun, the black quill and the slate-wing mahogany dun.

from a scientific perspective (i.e. there is no pupal stage between the larva and adult stages). The life cycle consists of four distinct stages, namely the egg stage, the nymph stage, the sub-adult stage, and the adult stage. The two adult stages are unique to the mayfly – during the sub-adult or sub-imago stage the mayfly is sexually immature.

The life cycle of the Leptophlebiidae mayfly starts when the sexually mature adults (i.e. sub-adults or sub-imagoes or spinners) mate during flight, after which the males die and fall to the water’s surface or onto surrounding land. The female of this family lays her eggs by dipping the end of her abdomen into the water’s surface, whilst flying low over the river or stream. The eggs sink, and due to current movement, are scattered along the substrate and between debris and aquatic vegetation. Upon hatching, the Leptophlebiidae nymphs live on the river bottom in slow moving or still water areas, sheltering from predators and currents by hiding under stones and debris – these nymphs are also protected by their camouflage. The nymphs are capable of running across the substrate and swimming for short distances only. In British fly fishing circles these nymphs are referred to as ‘laboured swimmers’. The nymphs feed on aquatic vegetation by removing algae and detritus from the undersides of stones and rubble.

The body design of the Leptophlebiidae nymph clearly reflects its specific habitat adaptation (i.e. slow moving or still areas in rivers and streams). The body exhibits the following physical characteristics:

A head – the head, which is square in appearance, bears compound eyes on each side, with three simple eyes situated in between the compound ones, and two front-facing, short antennae;
A clearly segmented thorax (three segments) – the thorax bears one pair of legs on each segment and a forewing pad on the second segment and a hind wing pad on the third segment (the wing pads give the thorax a ‘humped’ appearance); and
An abdomen – the abdomen consists of ten clearly defined segments, of which four to seven have gills attached, and three, long, well defined, spreading tails are found on the final segment (the tails are longer than their bodies).

The tails of the Leptophlebiidae nymph are generally much longer compared to most other mayfly families found in South African rivers and streams – only the Heptageniidae family could possibly rival it in terms of tail length. The surface areas of the gills of the Leptophlebiidae family are large, since this nymph occupies the slow-moving or still water areas of rivers and streams, and as such, it must produce current in order to take in enough oxygen. Each gill is split into two lobes and is either hair-like or leaf-like in appearance or a combination of both, depending on the specific species. The body colour of the nymph ranges from brown to dark brown. A reddish-brown body colouration is also occasionally found.

From a fly fishing perspective, the nymphal phase of the Leptophlebiidae family’s development is the most important stage to imitate. Since the nymphs of this family are generally quite large, trout love to target them, especially when they loose their footing and are washed away by faster currents. Regular seine netting performed in the rivers and streams in and around the village of Rhodes has revealed a preponderance of these nymphs right throughout the year.

Once the Leptophlebiidae nymph has fully matured, in terms of growth and age, it will either crawl out of the water onto a rock or tree trunk/branch, or it will ascend to the water’s surface in still water areas, where it will force its way out of its nymphal skin and unfold into an air-breathing, winged sub-adult, called a dun. In the North Eastern Cape Province of South Africa, the most prolific hatches of the Leptophlebiidae family occur in the late season (April/May) and early season (September/October). The dun sits almost motionless on the tree trunk/branch, rock or water’s surface until its wings and skin have hardened and dried sufficiently, after which it flies to waterside vegetation. Here it transforms into the final life cycle stage, namely the sexually mature adult (imago or spinner). Although North Eastern Cape trout prefer the nymph imitation, they will prey on the dun. The spinners, on the other hand, are not of any significance – the authors have never witnessed a fall of Leptophlebiidae spinners on the rivers and streams of the North Eastern Cape. In the United States of America the spinner of this family is generally also considered to be of little importance.

The body design of the Leptophlebiidae dun closely mimics that of the nymph. The obvious differences include, the absence of gill filaments (these are replaced by a “tracheal tube diffusion network” – see Whitlock) and the presence of two pairs of upright, sail like wings (the forewings are noticeably larger than the hind wings). The duns are not very colourful and have a very drab look. They generally average between 7 and 12 mm in size and have medium to dark brown bodies (only the spinners have reddish-brown bodies), slate grey wings (sometimes heavily mottled), three brown tails and six, well defined brown legs.

The Leptophlebiidae nymph imitation shown in the photograph above is the one preferred by the authors – it is the very famous and popular Zak nymph originated by Dr Tom Sutcliffe. What makes this pattern ideal is the dark appearance of the peacock herl used in the body construction and the long water mongoose or squirrel tail fibres used to simulate the tails. Moreover, the profile of the imitation, as required by the original recipe, also lends itself to the production of an impressionistic facsimile of the natural. The nymph imitations illustrated vary slightly in appearance and in tying method from the hardy original pattern tied by Dr. Tom, but works just as well. This imitation requires the following materials:

Hook: # 14 and 12 nymph hook

Bead: Optional, 2,3 – 2,6 mm gold bead on # 14 hook and 2,6 – 3mm on # 12 hook.
Thread: 8/0 Black
Weight: Optional but advisable, depending on the strength of the current.
Tail: 3 – 6 Squirrel tail, water mongoose or similar dark brown or black fibres the length of the hook shank or longer.
Abdomen: Three partly striped peacock herl
Ribbing: Copper wire and optional, 3- 4 turns of blue, copper or gold crystal flash
Thorax: Peacock herl
Legs (hackle): Sparse dark dun or black hackle

This imitation should be fished in the cushioned boundary layer just above the stream bottom, as deep as possible. It is not that the nymph necessarily drifts this deep but fish that avoid currents and lie within the cushioned boundary layer would rather accept a food source that drifts within range so that they do not exert too much energy reaching it. The Zak may be tied with a couple of turns of crystal flash and with a gold bead (that acts as a trigger and a weight) as in the photos, for fast flowing streams but in clear low waters it is advisable to use less flash and at times even exclude the bead. When targeting fish in slow or no current areas a Leisenring Lift or even the occasional hump mend would lift the fly off the bottom and imitate a fleeing nymph triggering a reaction. When the Leisenring lift is executed it helps to wiggle the rod tip to create an erratic swimming action. When fishing these imitations in fast currents, drag free, it is necessary to fish up or up and across using a strike indicator for depth control and strike detection. Fish often sample imitations in strong currents and spit the fly after realizing that it is not the real thing, the indicator will warn the angler to strike as soon as possible to set the hook. When fishing in slow or no current areas and using a Leisenring Lift, it is often not necessary to use an indicator as the take will be felt and the drag of the indicator on the water surface may alert fish. For maximum results, use a long tapered leader with 5X tippet (double figure fish are often landed on 5x tippet) and insure that drag does not have an effect on the fly.

The Leptophlebiidae dun imitation shown in the photograph above was developed by Fred Steynberg specifically to imitate the duns of this family found in the North Eastern Cape. The pattern is neither suggestive nor exact, but is impressionistic, and requires the following materials:

Hook: # 14 or 12 thin wire dry fly hook.

Tail: Brown or black deer hair or water mongoose fibres.
Abdomen: Ring neck pheasant tail fibres or mottled turkey tail fibres
Wing: Mottled or partly bared brown deer hair fibres
Legs (hackle): Dark Brown or red-brown hackle, cut level so that the fly sits with its body on the water surface.
Thread: 8/0 Black or dark brown

This imitation should be fished with a drag free drift in the slow or fast moving current areas with a long leader and 5X tippet.

South African Leptophlebiidae (prongills) nymphsadministrator2022-10-21T07:40:08+00:00