INSECTS were already established on the earth long before the arrival of either fish or Man. In their long history, over a million different kinds have evolved and they have adapted themselves not only to life in the air but, in many instances, to life on the ground and in the water as well. They serve as a very important food supply for fish, birds and also small amphibia such as frogs and toads. Although a few insects are pests, the great majority are either neutral to or actively beneficial to Man’s interests. The angler may occasionally curse the midges which pester him by the river bank but the apple, for example, which he may carry in his pocket, is the result of the pollinating activities of other insects.

Despite their huge numbers and the great range of life histories, often bizarre and curious, only a few insects are of particular interest to the fisherman. It should not take you long to learn how to recognise some of the more important ones and to choose a suitable imitation frorn your fly box.

Insects are arranged into groups or Orders on the basis of structural characteristics. Altogether, twenty-nine of such Orders exist, but only three or four are of direct importance as a source of food for fish. A very brief, generalised look at the life history of a typical insect from one of these Orders may help to explain how the angler attempts to relate his imitations to the stages in the life cycle of the insect.

Order Ephemeroptera

This group of insects, which has some sixty-nine British species or members, is the most important to the angler. The adults are easily recognisable by their membraneous and translucent wings, of which there are two pairs, the first or foremost being much larger than the hind pair. At rest, the wings are held in a vertical position above the body. This characteristic way of holding the wings has given rise to the name ‘Upright Winged Flies’. If one of these insects lands on your jacket, you may instantly identify it as a member of the Ephemeroptera. The entomologist sometimes refers to this order by the term ‘Mayflies’ but the angler usually restricts this name to a single member of the group which sometimes appears in large numbers about the end of May or the beginning of June. Fish feed so eagerly on the Mayfly, and are allegedly so easily caught, that the jocular name, ‘The Duffer’s Fortnight’ has been given to this period.

Life Cycle

The life cycle of members of this Order of insects can be divided into the following stages. First, the fully-developed adult male flies, or ‘spinners’, can be seen in aerial swarms by river or lakeside. After mating, the female seeks out water where she lays her eggs in batches. Some species deposit them just below the surface, others choose submerged rocks or weeds, and several thousand may be laid by one female. The eggs stick firmly to the river bed until they eventually hatch into nymphs. After mating and egg-laying, the insects die and the bodies of dead adults, floating down the water, are called ‘spent spinners’. Fish feed on these as well as on the live insects.


The nymphs differ in size, general appearance and habit but all possess three distinct tails and can thus be distinguished from the nymphs or larvae of any other Order. They are aquatic and obtain oxygen from the surrounding water by means of specialised ‘gills’ which are arranged as plate-like or filamentous appendages along the sides of their bodies. Some of these nymphs are a very important source of food for fish of all ages.

The outside ‘skin’ of the nymph is rigid and cannot expand as the insect grows. So, from time to time, the outer coat splits and is discarded, a process known as moulting. During the growth period, which may be as long as two years, great changes take place. Wings, for example, slowly develop in ‘wing buds’ and the wing cases in which they are protected can be seen on the ‘chest’ or thorax of the developing nymph.

Hatching to the Dun

Eventually, the moment arrives when the aquatic nymph is ready to moult for the last time and to emerge as the winged insect. Most species swim or float upwards to the water surface. There the outer coat splits down the top of the body and, often with astonishing speed, the winged aerial insect struggles free. Although it is now capable of flight, the insect belonging to this Order is not fully mature and must still shed a final coat. At this stage, it is called a dun.

After hatching, the dun may immediately take to the air, or it may remain for a time on the water. The last moult to the sexually mature adult takes place on trees or bushes near the water. Often a dun will land on your jacket and you may watch it shed its final ‘skin’ for yourself. The dun is usually somewhat colourless but when the adult, or spinner, emerges, the pigments in the body and the reflected and refracted light from the wings transform it into a creature of delicate beauty.

The fisherman may attempt to attract fish by imitating any of these stages in the life cycle of the insect, but, before we go on to look at the names of individual insects, let us examine the possible methods of fishing.

Nymph Fishing

The artificial fly is a representation of the underwater nymphal stage. It may be tied up to resemble the nymph of one species – that of the Mayfly, for example – but, more generally, it is a caricature which looks, more or less, like a number of different insects. Trout appear very much less fussy about the details of nymphs and often one general pattern, if fished in a convincingly ‘life-like’ manner, is quite sufficient to deceive fish successfully. Nymphs are often weighted with a few turns of fuse wire, which are incorporated in the tying process in order to make them sink more quickly. These are usually called ‘leaded’ nymphs.

Wet-fly Fishing

In this form of fishing, the flies are allowed to sink to various depths below the water. Wet-flies are tied up either with wings or without wings and resemble the adult aerial insects. The wingless variety are known as ‘spiders’ or hackled flies, and although this is a very successful form of fishing, it is difficult to understand just what the wet-fly is supposed to represent to the fish. Presumably, the winged types are taken to be drowned adult insects and the ‘spiders’ as nymph-like creatures. In tying wet-flies, the hackles (neck feathers) of hen birds are used, as these are softer than those from cock birds and sink better in the water. The softer fibres also vibrate more attractively with the movements of the current.

A number of wet-flies are tied up with silver or gold tinsel bodies and with gaudy wings. Some of them resemble beetles but most of them are not intended to represent a living insect at any stage. They are used as lures or ‘attractors’ and it is thought that they may be mistaken for small fish. Teams of two, three or four wet-flies are widely used in both river and lake fishing and a cast very commonly includes one of these brightly-coloured patterns.

Dry-fly Fishing

The dry-fly angler keeps his fly floating on the surface of the water where he can see it. He thus seeks to imitate the adult dun or spinner; frequently that particular species which is hatching at the moment and on which fish are feeding. Fine terminal nylon is often used and a single fly is cast to an individual fish which has been seen to rise. The flies are tied with the stiffer cock hackles which make them sit up on the water. To help them float, they are lightly dressed with special preparations which repel water. False casting, as previously explained, is necessary in order to keep the fly dry.

Dry-fly angling is sometimes regarded as the most skilful branch of the sport. So much so that the extreme exponent will fish in no other way and regards himself as a ‘purist’. In so doing he is, of course, pursuing a legitimate form of specialisation but not every fisherman agrees with, nor accepts, the mystique which has been fostered round dry-fly fishing. It remains a matter of personal choice which is best decided upon after experience of all branches of fly fishing has been acquired. Incidentally, on a few ‘dry-fly only’ waters, nymph or wet-fly fishing is not permitted, so you should enquire about any special rules before you start to fish.

Other Insect Orders

The Ephemeroptera, although of great importance to the fisherman, is by no means the only group on which he bases his artificial flies. At this stage, however, a very quick glance must serve to bring some of the others to your notice.

Caddis Flies (Order Trichoptera)

The larvae of these insects construct tubular cases using silk threads secreted from glands in their mouths. Around this silken tube, which serves as a portable home, they cement various materials such as sandgrains, watershells and bits of leaf. To the casual eye, they often appear as bits of stick and debris.

When fully grown, the larvae enter a quiescent phase called pupation. The winged adult insects, on emergence, are called sedges and silverhorns. They are somewhat mothlike in flight but the wings are free of the moth scales and this will help you to identify them. A number of fly patterns are used to imitate them, for example, the Welshman’s Button, the Grey Sedge and the Cinnamon Sedge.

Stone Flies (Order Plecoptera)

The nymphs have only two tails and can thus be distinguished from those of the Ephemeroptera. Some of the larger species are carnivorous and take a heavy toll of both caddis larvae and other nymphs.

The adult insects have hard, shiny wings which are crossed over the body at rest and this serves as a good clue to identification. When egg-laying, the females of the large stone flies create a characteristic V-shape ripple in the water, which undoubtedly helps to draw the attention of trout to their presence. The angler’s imitations include such flies as the Large Stone Fly, the Yellow Sallies and the February Red.

Building Up a Stock of Flies

There are literally hundreds of different patterns of flies from which to choose. Many beginners carry a wide variety at first, only to find later on that they actually use only a very few which become favourites. The most sensible advice is to find out the patterns most widely used on the waters you intend to fish and to stick to those at first. Local tyings often suit local conditions. For example, on the Clyde and Tweed, experienced fishermen use very lightly-dressed spiders; on Loch Leven, small, double-hooks are widely fished; on Chew and Blagdon, much larger hook sizes are used.

Besides the pattern, there is also the question of size. Again, this varies from the much larger hooks used in some lakes and lochs to the smaller river sizes favoured in other parts of the country. At present, there is some confusion about hook sizes, since two separate scales are in use – a so-called new one and an old one. It will help you to avoid misunderstanding if you learn to interchange them.

Old Scale of Hook Sizes

Nos.: 6 7 8 9 10 11 1A 13 14 15 16

New Scale

Nos.: 9 8 7 6 5 4 3 2 1 0 00 6?

For general purposes, the most commonly-used trout flies are Nos. 13,14, 15 and 16 in the old scale, and these correspond to Nos. 2, 1, 0 and 00 in the new scale.

Selecting a Fly on the Water

When insects are hatching out, the matter of selection is greatly simplified. Pick up one of the insects from the surface of the water and examine its size and colour carefully. Even if you cannot name it, you can choose the closest imitation from your box. Perhaps it is olive grey, in which case you could tie on one of your olive-coloured flies of about the same size. The ability to name the natural fly and to select the appropriate artificial, will come with practice. Often fish may not be particularly fussy about what they will accept – at other times, they may be very difficult to satisfy. This is all part of the fun and the skill of angling. If fish are moving freely to the surface fly, then dry-fly is the method of choice. If no fish are to be seen rising, then you may do better if you search the water with a team of wet-flies. The good angler varies his tactics to suit conditions, and alters them as conditions change.

When no fly is out at all, you are then forced to select your flies for pattern and for size without any natural help. This is not the difficult task that it may sound. Most anglers have a team of favourites, consisting of three or four patterns, which they fish successfully throughout the whole season. Some flies, such as the March Brown, Greenwell’s Glory, the Pheasant Tail and nymphs, can be used almost anywhere. Here are a few of the more widely-used patterns.


Ginger Quill

Pheasant Tail

Iron Blue Dun

Black Gnat

Orange Quill

March Brown

Medium Olive

Silver Sedge

Wet-flies (River)

March Brown

Snipe and Purple

Partridge and Orange

Wickham’s Fancy

Greenwell’s Glory

Black Spider

Gold Ribbed Hare’s Ear

Hardy’s Favourite

Wet-flies (Lake) Peter Ross Butcher

Grouse and Claret Jersey Herd


Woodcock and Yellow Blae and Black Teal and Red