Heptageniidae (Ephemeroptera) of Wisconsin

Abstract

Ephemeroptera is a small order of Pterygota, with approximately 3500 species worldwide. With around 820 species described so far, the Neotropical realm presents the highest diversity. All the immatures spend their lives in freshwater environments, while the adults (including the unique, subimaginal stage), are aerial. The name of the order reflexes the short life-span, which can vary from species living only a couple of hours to others that can extend up to a week in some ovoviviparous species. They are so specialized that the adults have an atrophied digestive system, and in some species the adults loose part of their legs when molting from the nymphal skin. They are important components of the freshwater fauna, inhabiting a wide range of microhabitats and covering different trophic roles. As such, the mayfly species are present in most freshwater samples, making critical their identification for limnological studies. Up to now, most of the keys were circumscribed only to continental South America, to Central America, or to the Caribbean. This chapter provides for the first time updated nymphal identification keys for Neotropical families and genera. All the characters used in the keys are illustrated.