If asked to name one single type of aquatic insect, most people would admit to being stumped, as aquatic insects are not well known to the public. This makes sense, considering that very few aquatic insect species exist. While there are certainly several species of aquatic insect, they are relatively few in number when taking into account the total amount of existing insect species that have been documented within the past one hundred or so years. Although most people are likely under the impression that they have never seen an aquatic insect species before, there is one type that is actually quite common all over the world. This insect type is known as a hellgrammite, and citizens of the the northeast US encounter these insects more often than any other population of people in America. However, hellgrammites are not always recognized as insects, as they resemble other forms of aquatic animals more so than a typical six-legged insect.


To call hellgrammites “aquatic insects” may be somewhat misleading, as the term “hellgramite” is the name given to the larvae of dobsonflies. Dobsonflies are not considered aquatic insects, but their larvae, hellgrammites, live solely in marine environments. Dobsonflies spend most of their lives as hellgrammites living in bodies of water. Specifically, hellgrammites emerge from natural sources of freshwater, such as rivers or lakes, as winged flies following a period of around three years of living as aquatic larvae. Dobsonflies only live as winged insects for a period of days; males live for around three days, while females last for around ten days. Given the striking difference in lifespan and appearance between mature dobsonflies and their larval counterparts, hellgrammites are not usually associated with flies. This is the main reason why dobsonfly larvae have earned their own title.


Hellgrammites are notable for their large jaws and centipede-like appearance. The fierce looking jaws that belong to these larval insects make them one of the fiercest types of aquatic insect predators. The jaws belonging to male hellgrammites are too small to puncture human skin, but the female’s jaws are not. Luckily, humans are rarely bitten by hellgrammites, and due to their abundance, they are often used as bait by fishermen.


Have you ever seen a hellgrammite or used one as bait while fishing?