The dobsonfly spends two to three years of its life as a predaceous larva called hellgrammite in streams and rivers. When Hellgrammites get full-sized, they crawl from the water and find a safe spot to overwinter in a coccoon. The following summer, the adult Eastern Dobsonfly will emerge only to mate. They live just a few days and don’t eat.
The adult males have huge, ferocious looking jaws, which are used for nothing else but clasping the female during courtship. The adult females have much smaller looking mandibles. After the adult dobsonflies mate, the female lays eggs on a branch or on rocks near a stream. Between 100 and 1,000 eggs are laid in a mass with a white substance over it. The eggs resemble bird droppings, which may protect them from predators.
Hellgrammites, after they hatch, will either fall into the stream from an overhanging branch, or crawl to the water and the process starts all over again. There are over 220 species of dobsonflies found throughout the Americas and Asia, as well as South Africa. They are sensitive to contaminates in the water and a good indicator that the water is clean.
2. Insects of the North Woods by Jeffrey Hahn
- Tiger moths: What is that white moth with black spots?: http://bit.ly/rtneuz
- A Very Tiny Hummingbird (Moth)?: http://bit.ly/qtrAaV
- Why did I take a picture of bird poop?: http://bit.ly/o9APHb
- Where does the Woolly Bear go in the winter?: http://bit.ly/pB5L4V
- Brown bark-colored moth with orange stripes on body http://bit.ly/Lcp0eb