The Significance of Nymphal Stages in the Study of Ephemeroptera

The aquatic nymphs and aerial adults offer 2 different sets of characters for study. Knowledge of the nymphs is essential for clarifying relationships and testing the validity of species concepts. The demand for specific identifications also is greatest for the nymphs, and the long-lived nymphs are more abundant in collections than are the short-lived adults. Despite the greater need for knowledge of nymphs, the adults are much better known. Field and laboratory rearing is needed in almost all parts of the world to associate adults and nymphs and provide the knowledge necessary for an adequate taxonomy. Association of adults and nymphs collected together in the field is useful if rigid precautions are observed. The authors suggest that the naming of species from nymphs only is useful when an appropriate effort is made to associate adults and nymphs of all species and the studies are revisional. Analysis of the cause of synonymies where some species have been described from nymphs only and some from adults only shows that very few synonymies result from such practices.