Mayfly

Immature mayflies are aquatic and are referred to as nymphs or naiads. They have an elongated, cylindrical or somewhat flattened body that passes through a number of instars, molting and increasing in size each time. The final moult of the nymph is not to the full adult form, but to a winged stage called a subimago.

About Mayfly in brief

Over 3,000 species of mayfly are known worldwide, grouped into over 400 genera in 42 families. Immature mayflies are aquatic and are referred to as nymphs or naiads. They have an elongated, cylindrical or somewhat flattened body that passes through a number of instars, molting and increasing in size each time. The final moult of the nymph is not to the full adult form, but to a winged stage called a subimago that physically resembles the adult, but which is usually sexually immature and duller in colour. After a period, usually lasting one or two days, the subimagos moults into a full adult, the imago, making the insects only last a few minutes to a few hours in the water. The English poet George Crabbe compared the brief life of a daily newspaper with that of a mayfly in the satirical poem ‘The Newspaper’. The German engraver Albrecht Dürer included a may fly in his 1495 engraving The Holy Family with the Mayfly to suggest a link between heaven and earth. In some species the gills are instead located on the coxae of the legs, or the bases of the maxillae. The abdomen terminates in a pair of, or three, slender thread-like projections. Some mayflies do not oult from a nymph state into an adult stage and are sexually mature while appearing like aSubimago on the wing. Oligone mayflies form another exception, retaining an adult state and retaining microtrichia on their wings but not on their bodies.

In males of Ephoron leukon, the Subimagos have short forelegs that are short and compressed with accordion-like folds that are like accordion folds, like folds, and expands to more than double its length after moulting. In females of some mayflies, such as the Oligine mayfly, the wings are fringed with minute hairs known as microTrichia; its eyes, legs and genitalia are not fully developed. Mayflies are generally poor fliers, have shorter appendages and typically lack the colour patterns used in the patterns used by fly fishermen to attract mates. They are unique among insect orders in having a fully winged terrestrial preadult stage, thesubimago. The mouthparts are designed for chewing and consist of a flap-like labrum and pair of strong mandibles. The thorax consists of three segments – the hindmost two, the mesothorax and metathorax, being fused. The legs are robust and often clad in bristles, hairs or spines, and in some species, hindwing pads develop on the metath orax. The head has a tough outer covering of sclerotin, often with various hard ridges and projections; it points either forwards or downwards, with the mouth at the front. In most taxa up to seven pairs of gills arise from the top or sides of the abdomen.