Image Credit: Amy L. taken in Great Falls Park, MD
The large jaws and long mandibles on a male Dobsonfly may cry 'caution', but it's the fierce bite from a female that should have you on guard.
Male Dobsonflies look quite fearsome, with what appear to be tentacle-like appendages for mouth parts. The truth is, the males of the species cannot bite and are considered harmless to humans. The females, on the other hand, can deliver quite a painful bite from her strong jaws if she is agitated. Male Dobsonflies have long, fleshy mandibles that can look like a second set of short antennae. Females have a short jaw with large pincers. Both genders are a taupe color and have large wings that cover the body when viewed from overhead. The net-veined wings have small white dots on them and they slightly overlap at the midline.
Dobsonflies begin life as aquatic larvae before graduating to status as an airborne insect. They feed on tadpoles, small fish, and other young aquatic larvae from other species (like dragonfly naiads and stonefly hellgrammites). Larvae look like underwater centipedes early in life, and adults keep watch over them from a nearby area above the water. All larvae can bite, requiring care when handling. The threat of a nip on the finger does not stop anglers from using them as live bait.
Adults are primarily nocturnal (night dwellers) and are naturally drawn to light sources at night. They do not eat. Instead, they spend their days focused on reproducing the next generation of Dobsonflies.
Scientific Name: Corydalus cornutus
Alderfly or Dobsonfly
Size (Adult; Length): 50mm to 127mm (1.95in to 4.95in)
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