大象传媒

Flowing towards the English Channel, the shallow clear chalk streams of Hampshire are famous for their trout and for the mayflies which rise in early summer. Mayfly nymphs may spend up to three years underwater, breathing through feathery gills. When ready to emerge they rise to the surface where, upon contact with the air, they struggle to escape their larval case. But then they have the trout to contend with. The fishing flies of an angler - and the angler's movements - are designed to fool the trout into biting. However, mayfly that do manage to break free of the water's surface fly to riverside plants to complete the first stage of their transformation. The mayfly is unique among insects in that it emerges as an immature form, perfectly equipped with wings but incapable of mating. These duns, as anglers call them, will moult into adults within hours.