Megaloptera

Article By:

Contreras-Ramos, Atilano. Departamento de Zoologia, Instituto de Biologia, Universidad Nacional Autónoma de México, Mexico City, Mexico.

Last reviewed:January 2020

DOI:https://doi.org/10.1036/1097-8542.900190

A small order considered among the most primitive holometabolous insects. Along with Neuroptera and Raphidioptera, Megaloptera forms part of the superorder Neuropterida, which is recognized generally as a sister group to Coleoptera. Despite a low diversity of about 340 described extant species, Megaloptera includes some of the most impressive insects. Males of the New World Corydalus (Fig. 1) and Asian Acanthacorydalis bear elongate mandibles, which provide them with a dangerous appearance, yet they are harmless to humans and possibly are used as weapons to fight for mates or perhaps to impress females. North American Corydalus may reach a wingspan of about 132 mm (5.3 in.), whereas their aquatic larvae (hellgrammites) may reach a length of 65 mm (2.6 in.) or more. Megaloptera is divided into two families, Sialidae (alderflies) and Corydalidae, which is subdivided further into Corydalinae (dobsonflies) and Chauliodinae (fishflies). Megaloptera is a cosmopolitan group (having a worldwide distribution), with all species having aquatic larvae; in contrast, the eggs, pupae, and adults are terrestrial. In the New World, Sialidae is more diverse in the Nearctic (the zoogeographic region that includes all of North America to the edge of the Mexican Plateau), whereas Corydalinae is more diverse in the Neotropics; species of Chauliodinae are Nearctic and Chilean. See also: Insecta; Neuroptera

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