Craneflies are commonly called “Daddy-Long Legs,” “Mosquito Eaters,” or “Mosquito Killers.” Entomologists call them the family Tipulidae. Most fly anglers don’t call them anything, believing they are irrelevant to their fishing. Too bad, because trout often call them “lunch.”
Larvae – Craneflies
Most people will recognize an adult cranefly: fairly skinny body, very long and frail legs, and long wings which usually lie over the back. However, the larvae of these insects are probably foreign to anyone who has not actively pursued them.
Larvae resemble thick worms, with a usually cylindrical, occasionally flattened, body that is somewhat blunt at the head and slightly tapered at the rear. Colors are often drab, with grays, light olives, and light tans being most common. They are easily distinguished from other large aquatic grubs because of their retracted head.
Most cranefly larvae are terrestrial, making their home in the soil near, but not under, streams. There are some aquatic tipulids, and these larvae are most common in mossy bottoms or in areas where the riparian soil is often too dry or rocky to allow good burrowing.
When the larvae of craneflies are washed into a stream, they are very much sought after by trout. The larvae of craneflies have no swimming ability whatsoever, and once they are caught up in the drift, they are goners.
Imitating the larvae is a simple endeavor that is much more dependent on when you fly fish, rather than how. Most fly anglers avoid streams in the day or two after a heavy rain, preferring to tie flies or perform other household chores, but I can usually be found on the river somewhere, lobbing larva imitations under a big indicator.
The days following a rain are prime-time, maybe the only time, where fly fishing cranefly larvae can be very productive
It is best to dead-drift larva imitations near the bottom, for the naturals have no swimming ability. Also, keep your imitations near shore, where the larvae originated; fish in this area are more conditioned to seeing the naturals. Of course, fishing cranefly imitations on small streams, where the shoreline is always nearby, is much better than on large streams.
Flies for the larvae of craneflies are very simple, because the shape of these insects is more or less that of a worm or grub. Since many of the larvae are translucent, a thin dubbed body of pale-olive, gray-olive, or dark gray dubbing, brushed out and clipped short, with a head of black ostrich herl, can be a deadly pattern.
Pupae and Emergence – Craneflies
The pupa stage of craneflies is largely unimportant to fly anglers. Almost all cranefly larvae, terrestrial and aquatic, migrate to stable ground near streams to pupate. They pupate under the soil (or leaves and logs, if the soil is unsuitable), for one to two months. Because cranefly emergence is spread throughout the spring, summer, and early fall, and since pupation is done on land, the exact emergence period is of no significance to anglers. Adults of both aquatic and terrestrial craneflies start to emerge during April to late May. They continue to emerge throughout the summertime. Adult numbers wane slightly in the mid-summer, but increase as September rolls around.
Adults – Craneflies
Adult craneflies are clumsy fliers, so they are sporadically available to trout.
Adult craneflies prefer the shady and cool riparian zone during the summer, and can be found hanging around ferns and the rootwads of fallen trees, as well as streamside rocks and brush
Most adult “imitations” you see in America are rather amateurish. Spider patterns or things that look like big midge patterns.
To look for good imitations, you need to open a book or magazine on English flyfishing. They made fishing “the daddy” an art, and really have some amazing patterns.
Adult imitations are particularly effective in two locations: small streams with dense overhead canopies that provide near-constant shade, and tailwaters. In both these locations, adult activity is at its maximum on calm, warm evenings. I rarely pull out adult cranefly patterns in the heat of the day, preferring to wait until the shadows hit the water.
When fly fishing adult imitations keep them near shore, where fish are likely to have encountered the natural before. It can be effective to skate these patterns by greasing them with floatant and skittering them across the surface. Despite the aggressive strikes this technique can produce, it is rarely more effective, day-in-day-out, than a simple dead-drift.