Insect Order Plecoptera (Stoneflies)
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Kingdom Animalia (Animals)
» Phylum Arthropoda (Arthropods)
» Class Insecta (Insects)
» Order Plecoptera (Stoneflies)
Common Name
| Match | Common Name |
 | Stoneflies |
Fly Imitations by Orvis
| Stage | Fly Pattern |
| Nymph | Kauffman's Stone |
| Adult | Stimulator |
The best stoneflies for the angler are the gigantic Pteronarcys californica "Salmonflies" of western legend. The large Golden Stones of the Perlidae and Perlodidae families are more common across the country. The smaller Willowflies of Taeniopterygidae are sometimes the first dry-fly insects of the season, and the little yellow or green Chloroperlidae flies are a common sight throughout the summer.
Hatching Behavior
Stoneflies owe their unimportance to their emergence style, which keeps them safe from trout at a stage when mayflies and caddisflies are the most vulnerable. Without exception, they emerge by crawling out of the water onto rocks, sticks, or other shoreline objects. In some species the adult emerges from the nymph within inches of the water, and others crawl up to ten feet back into the woods, but this distinction matters little to the trout.After emerging, the adults may live for up to a month. Like caddisflies and unlike mayflies, many stonefly species can eat and drink as adults.
Egg-Laying Behavior
Stonefly adults are usually only important when laying their eggs after mating. Some drop their eggs from above the water but many either flutter along the surface or land on the water and create a commotion capable of drawing savage strikes from large trout during midday. They are one reason for the success of the Stimulator dry fly in large sizes.Stoneflies may fall spent (Spent: The wing position of many aquatic insects when they fall on the water after mating. The wings of both sides lay flat on the water. The word may be used to describe insects with their wings in that position, as well as the position itself.) after ovipositing.
Juvenile Biology
If stonefly nymphs were mayflies, they would all be classified as "clingers." They have double claws on their tarsi (Tarsus: The often multi-segmented outer leg section of an insect, which attached to the tibia.) which help them grip and clamber over fast-water rocks, and many of them have flattened bodies to make clinging even easier. Some species are better adapted to slow water, but they are not as common.
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Although there are also plenty of small species, most of the largest insects in a trout stream are likely to be stonefly nymphs. They are poor swimmers, so when they occasionally slip into the drift (either by accident or durnig behavioral drift (Behavioral drift: The nymphs and larvae of many aquatic insects sometimes release their grip on the bottom and drift downstream for a while with synchronized timing. This phenomenon increases their vulnerability to trout just like emergence, but it is invisible to the angler above the surface. In many species it occurs daily, most often just after dusk or just before dawn.)) they are prime targets for trout. This makes stonefly nymph imitations popular and successful searching patterns (Searching pattern: Any artificial fly pattern used when trout that aren't feeding selectively on anything in particular. A searching pattern may be an attractor or an imitation of something specific that the fish might favor even though it's not currently hatching.) during non-hatch periods.
When the emergence of an especially abundant species is near, its nymphs may be so active and concentrated that trout feed on them selectively near the emergence sites. This is more common in the West where the cool, swift rivers draining the Rockies hold remarkable stonefly populations.
58 Stonefly Specimens:
Cultus Stonefly Nymph
View 11 PicturesThis large Perlodidae stonefly was a strikingly bright yellow color, moreso than any other insect I've seen. I didn't enhance it much. I tried identifying its genus and came up with Arcynopteryx. Someone who seems to know more suggested Cultus instead. See the discussion thread.
View 11 PicturesThis large Perlodidae stonefly was a strikingly bright yellow color, moreso than any other insect I've seen. I didn't enhance it much. I tried identifying its genus and came up with Arcynopteryx. Someone who seems to know more suggested Cultus instead. See the discussion thread.Region: Catskills
Collected Apr 19, 2006
Added Apr 22, 2006
Isoperla (Yellow Sallies) Stonefly Adult
View 14 PicturesA friend brought me this stonefly to photograph. He found it floating on the surface of a trout stream with its wings in a crippled position.
View 14 PicturesA friend brought me this stonefly to photograph. He found it floating on the surface of a trout stream with its wings in a crippled position.Region: Northeast
Collected May 5, 2006
Added May 22, 2006
Pteronarcys dorsata (American Salmonfly) Stonefly Nymph
View 8 Pictures
View 8 PicturesRegion: Upper Midwest
Collected Feb 7, 2004
Added Jan 25, 2006
11 Streamside Pictures of Stoneflies:
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Several large stoneflies recently emerged and left their nymphal skins on this log in fast water. Imitating the fluttering adults helped me hook a couple trout.
In this picture: Stonefly Family Perlidae (Golden Stones).
In this picture: Stonefly Family Perlidae (Golden Stones).
Large stonefly nymphs sometimes crawl quite far from the water before emerging. This empty case is from a nymph that hatched about 5 feet up in a tree 10 feet from the river.
In this picture: Stonefly Species Pteronarcys dorsata (American Salmonfly).
In this picture: Stonefly Species Pteronarcys dorsata (American Salmonfly).
When the freshly shed nymphal skins of large stoneflies cover a log like this, imitating the nymphs is a good bet for large trout.
In this picture: Stonefly Family Perlidae (Golden Stones).
In this picture: Stonefly Family Perlidae (Golden Stones).
6 Underwater Pictures of Stoneflies:
The mayfly and stonefly nymphs in this picture blend in extremely well.
In this picture: Mayfly Species Ephemerella invaria (Sulphur) and Insect Order Plecoptera (Stoneflies).
In this picture: Mayfly Species Ephemerella invaria (Sulphur) and Insect Order Plecoptera (Stoneflies).
There are several mayfly and stonefly nymphs clinging to this log.
In this picture: Mayfly Family Baetidae (Blue-Winged Olives) and Stonefly Family Taeniopterygidae (Willowflies).
In this picture: Mayfly Family Baetidae (Blue-Winged Olives) and Stonefly Family Taeniopterygidae (Willowflies).
Recent Discussions of Plecoptera
Winter Stones and the like 3 Replies »
Last reply on May 21, 2008 by Greenwolly
I like your site and all it offers. Would like you to come on down to the Southeast and identify our species of mayflies, caddis and plecoptera. Ours are a bit different in makeup than elsewhere and really need cataloging. We constantly are trying to compare our species to the northern hatches and it does not fit into their pattern. We are a month ahead of everywhere else and twice as long in many cases. Some hatches seem to be identifiable and then some defy easy categorization.
DarkDun
ReplySalmonfly question for you westerners 4 Replies »DarkDun
Posted by Troutnut on Jul 30, 2006 in the species Pteronarcys californica
Last reply on Apr 25, 2008 by Aaron7_8
I don't have many reliable sources about this species, so it'd be great if you western fishermen could read over the article and make sure I haven't said anything stupid or omitted anything important. I'll be happy to incorporate any additions you have.
ReplyQuestion 7 Replies »Posted by Max29 on Jan 29, 2008 in the species Pteronarcys dorsata
Last reply on Jan 30, 2008 by Taxon
Are stoneflies and salmonflies the same thing or are they just related because here in the mid west we have the stonfly hatch and if they are related the stonfly could be called the salmonfly and the salmonfly hatch is only in the west because I have trouble because I want to become a better insect identifier when it comes to fishing because i went to other sites that so a stonefly is a stonefly and a salmonfly is a salmon fly but yet you say stonefly nymph but in parenteseses you have american salmonfly so is there really no such thing as a salmonfly but it is rather called a stonefly.
ReplyHigh Water 5 Replies »Posted by Dbar on Apr 13, 2007 in the species Pteronarcys californica
Last reply on Apr 20, 2007 by Riverratben
The hatch often occurs during high water (just after peak) so you sometimes have limited visibility during the hatch. Also - I believe that they can occur above 7000 feet.
Love ths site.
ReplyLove ths site.
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