Aquatic Insects and Fly Fishing
At least four orders of aquatic insects receive substantial interest from fly fishing enthusiasts, rivaling the interest shown by the agriculture sector to beneficial and harmful crop insects.
Caddisflies, Dobsonflies, Mayflies and Stoneflies provide fly fishers a dual benefit. The transition from their early water environment to their winged environment provides a visual aide helpful for identifying potential fishing hot spots.
Larvae also serve as live bait or as models for constructed flys. Thousands of species populate clean water bodies across North America.
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Types of Insects
The image on the right shows three of the four aquatic insect orders discussed in more detail, dobsonfly, mayfly and stonefly.
Their relative abundance in any given area serves as an indication of water quality.
With over twelve hundred documented North American species, the extended antennae (clipped in the above picture of Nemotaulius hostilis) serve as the initial Trichoptera identifying tool.
Caddisflies go through complete metamorphosis, with the egg, larvae and pupa stages occurring under water, and the adult stage occurring on land.
Like spiders, caddisfly larvae have the ability to produce silk, and they use this ability to build themselves protective cases.
Dobsonflies, winged insects in the family Corydalidae, also fit into the larger neuropteran order with lacewings
The larvae found in streams and ponds historically used as fish bait.
Wings folded above a long thin body ending in two long tails clue the wildlife watcher into the presence of the Mayfly (Order Ephemeroptera).
Over six hundred Mayfly species have been documented for North America, and they can be found flying, often in big swarms, around freshwater sources from spring through fall, depending on the species.
Like other aquatic flies such as stoneflies and caddisflies, their abundance in an area is indicative of water quality. Their aquatic life stages of nymph and emerger, which on average lasts about one year, eventually transition into land stages.
During the transition from water to land, hungry fish keep their eyes peeled for caddisfly snacks. Astute fly fishers learn about the hatch times for caddisfly species in different locations in order to improve the odds of a successful outing.
Two additional life stages remain for those Mayflies that make it to land. In the first stage, mayflies go by the name dun, the name given for the winged, but not yet adults of the species. After a day or so, duns molt, becoming an adult, whereupon their name changes to spinner.
The spinner's life last one day, as adults take flight over the water to mate. Hungry fish anticipate the spinners falling back to the water at the end of their life span.
Stoneflies (Order Plecoptera) might be considered one of the trout fisherman's VBF, very best friends.
Nine stonefly families, consisting of over six hundred species have been documented in the United States.
All share some common traits. They are aquatic insects that go through a life-cycle consisting of a water phase (egg to nymph) and a land phase (flying adult). The cycle is called incomplete metamorphosis because they skip the pupa stage.
Nymphs, like the one in the top picture have two tail-like cerci on the end of the abdomen. They can be confused with Mayfly nymphs, which have three long tails.
They are very sensitive to water quality, and in areas where they are found in large numbers, the nymphs are an important food source for native trout.
© 2007-2012. Patricia A. Michaels