About Nigronia serricornis (Say, 1824)
Nigronia serricornis (Say, 1824) has several common names: hellgrammites, fishflies, and saw-combed fishflies. The genus Nigronia contains one additional North American species, N. fasciatus, as well as a South American species that occupies much of the same range and is very similar to N. serricornis in all aspects. These are holometabolous insects with an aquatic larval stage. N. serricornis is a common inhabitant of woodland streams in North America, and is often the largest insect predator found in 2nd and 3rd order streams. The larvae are sit-and-wait ambush predators that feed on a wide variety of invertebrates, and studies show that N. serricornis has a diet that changes across seasons. Despite having limited dispersal ability, this species has spread across the Eastern United States. Its range extends north from Florida into Ontario, and west as far as the Rocky Mountains in the United States. Genetic analyses conducted by Heilveil and Berlocher in 2006 identified six major clades of N. serricornis. The ancestral clade, located at the northern end of the species' range, represents the initial colonization of N. serricornis in the Eastern United States. This ancestral clade is separated from the derived clade by the Appalachian Mountains.
