Dobsonflies

Benthic Macroinvertebrates

Sensitive Benthos

Moderately Tolerant Benthos

Pollution Tolerant Benthos

Dobsonfly larvae

Metamorphosis:

complete (see our life cycle page for more information)

Larvae:

often called hellgrammites, possess two large mandibles; several filaments are located along the sides of the abdomen; one pair of short tail filaments used for grasping; color brownish to black with a large dark "plate" behind base of head; six legs; length up to 3 inches.

Reproduction:

female attaches eggs on overhanging vegetation; when eggs; hatch, the larvae fall directly into the water.

Adults:

possess two pair of extremely long, colorful wings folded back the length of the body; males possess a pair of long mandibles that can cross that are used to grasp the female during copulation, females possess one pair of mandibles smaller than those of the male.

Food:

Close-up of dobsonfly larvae mandibles

predaceous larvae feed upon other aquatic macroinvertebrates; larvae widely used as fish bait; important food source for larger game fish.

Scientific Name:

Class: Insecta
Order: Megaloptera
Family: Corydalidae

Indicator Role:

dobsonfly larvae are considered fairly intolerant to pollution

Information Source:

McDonald, B., W. Borden, J. Lathrop.1990. Citizen Stream Monitoring: A Manual for Illinois. Illinois Department of Energy and Natural Resources, ILENR/RE-WR-90/18. Springfield, Illinois.

Other Links:

Close-up of dobsonfly larvae gills

Corydalidae (Dobsonflies, Fishflies, Hellgrammites) - Aquatic Insect Interactive Verification Program - Chironomidae Research Group, University of Minnesota
Dobsonfly larvae from the Kentucky Biological Stream Assessment Water Watch Biological Monitoring Procedures
Megaloptera in Freshwater Benthic Ecology and Aquatic Entomology Homepage – S.M. Mandaville from the Soil & Water Conservation Society of MetroHalifax
Tree of Life - Dobsonflies

Biological Indicators | Aquatic Biodiversity | Statistical Primer