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.

Swimmer dragonfly nymph

South Africa Dragonfly nymph fly

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.

Gomphidae(burrower) imitation:

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

Corduliidae and Libellulidae imitations (crawler)

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

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.