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Dobsonfly ManyPeopleDoNotKnowWhatAnAdultDobsonfly LooksLike.However,ManyOfThoseSamePeople CouldEasilyIdentifyTheImmature(Larval)Stage

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Dobsonfly Many�People�Do�Not�Know�What�An�Adult�Dobsonfly Looks�Like.��However,�Many�Of�Those�Same�People Could�Easily�Identify�The�Immature�(Larval)�Stage by Rich Wood Dobsonfly Manypeopledonotknowwhatanadultdobsonfly lookslike.However,manyofthosesamepeople couldeasilyidentifytheimmature(larval)stage. It’scalledahellgrammite.Dobsonfliesbelongto theorderofinsectscalledMegaloptera. The fierce-looking, winged dobsonfly has a life Emergence cycle that lasts two to five years. They have com- The larvae crawl out of the water and carefully plete metamorphosis. This is sometimes referred choose a location. This site may be up to 50 feet from to as ELPA: Egg, Larva, Pupa, Adult. The larval the water. Hellgrammites dig underground a few cen- stage, nicknamed a “hellgrammite,” is the most timeters or may burrow under dead leaves, a rotten log familiar. These active critters are well-known by or old tree stump. Here they change from larvae into anglers and people who study aquatic life. pupae. The pupal stage may last from one to 14 days. Hellgrammites play an important role in the food Most dobsonflies in Pennsylvania emerge in spring chain. They are major underwater predators and and summer. are eaten by many species of fish. Dobsonflies are usually nocturnal. Adults Adult dobsonflies live only a few days. They are Larvae large, weak fliers. Males have much longer mandibles Hellgrammites are usually found in cool rivers than females. They use these “long jaws” to fight and streams. They may also occur in lakes and other males and grasp females for mating. Adults are ponds. They require good water quality with high eaten by many fish, birds and bats. amounts of dissolved oxygen. They live on the bot- tom and with strong legs cling to rocks and sticks. Mating They can also swim easily forward or backward by Using their long mandibles, males grab females wiggling their entire body. They may grow up to 5 around their wings. Mating usually takes place on the inches in length. They have a strong set of man- ground or on vegetation. dibles (mouth parts) that can catch, hold and eat many aquatic insects and even small fish. These Eggs “pinchers” can grab anything that comes close to Eggs are laid in masses, with many eggs in each them, including unsuspecting fingers! Larvae mass. Females deposit their eggs out of the water. breathe oxygen from the water through well-devel- They may use bridge abutments, overhanging vegeta- oped tufted gills on the abdomen. They may also tion or rocks that stick out of the water. Hatching live out of the water by using spiracles (breathing takes place at night as the new larvae drop into the tubes) on the abdomen to breathe air. The larval water. Young larvae may hatch in a few days or may stage may last one to three years. take up to two weeks. 46 Pennsylvania Angler & Boater www.fish.state.pa.us Thereareabout50differentspeciesofMegalopterafoundin NorthAmerica.Thisgroupincludesdobsonflies,fishfliesandalderflies. illustration-Ted Walke www.fish.state.pa.us Pennsylvania Angler & Boater 47.
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