Nearly a million species of insects have been described by entomologists. I have left several of them off of this site, just to save time, but I've tried to include all the main aquatic insects trout eat in North America.
» Class Insecta (Insects)
1 order isn't included.
This site focuses on aquatic insects, of which the most important are mayflies (Ephemeroptera) and caddisflies (Trichoptera). Stoneflies (Plecoptera) come in third, a position arguably challenged by the many two-winged true flies of the Diptera order, which includes midges and craneflies. I've also included some terrestrial (Terrestrial: Insects which live on land and are fed on by trout only when they incidentally fall into the water are known as "terrestrials" to fly anglers, and they're very important in late summer.) insects which I've found on or near trout streams. Terrestrials (Terrestrial: Insects which live on land and are fed on by trout only when they incidentally fall into the water are known as "terrestrials" to fly anglers, and they're very important in late summer.) like ants, beetles, and grasshoppers are an important food source for trout in many places, especially during the summer months.
Aquatic insects do not live their entire lives in the water. Instead, they grow for a year (give or take quite a bit) as nymphs or larvae underwater, and then they emerge into air-breathing winged insects for a short while to mate and die. There are many variations on this theme.
The most important aquatic insects for fly fishermen are mayflies, stoneflies, caddisflies, and midges. Mayflies and caddisflies are the most discussed by angler-entomologists, because it's so useful to closely identify them. The behavior of their species guides the behavior of feeding trout, and an angler who understands the lifecycle of a particular species has the upper hand when it's hatching. This is not so important for stoneflies and midges, because their hatching behavior is less variable.
Pictures of 1002 Insect Specimens:
1 Streamside Picture of Insects:
Date AddedSep 5, 2017
CameraNIKON 1 AW1
114 Underwater Pictures of Insects:
Underwater Photo Page:1234
Date AddedApr 22, 2006
CameraPENTAX Optio WPi
Underwater Photo Page:1234
Recent Discussions of Insecta
Polymitarcyidae Question 1 Reply »
What size are these nymphs & Sub Imago's?ReplySteamntrout
Looking at Purdue's May Fly Central it shows nebulosa being found in Canada's Far North, North East and North West as well as USA's North East, South East & Far West.ReplyClinger nymphs are shaped that way to hang in really fast currents. Really? 14 Replies »
It is commonly held that clingers are flattened to make their lives better adapted to faster water. Their teardrop shape is certainly a classic symbol of aero and hydrodynamic perfection, so there must be some connection, right? It seems to me that such ideas show a complete misunderstanding of the hydraulic reality in which they live. Current is negligable even in the fastest a few mm. from the surface of solid objects. In fact, it is actually quite calm. I've observed baetids clinging by their tippy toes to the tops of rocks in fast riffles with no apparent effort, often next to clinger species that look like they're hanging on for dear life. What if clinger nymphs are flattened not to hold their place in fast currents but rather to facilitate movement in their ecological niche of the cramped spaces under and between cobble or crevices in other substrate types?ReplyHigh Water 8 Replies »
It is also thought that the gills of some species form ''suction'' to hold them in place. Since suction is a phenomena of vacuum creation in the atmosphere, how are these nymphs accomplishing this underwater? Is it their ultra delicate gills that hold them in place or a firm claw grip? The horizontal sprawl of the legs masks this as the gills stay in place until the legs brake free. Exposed to the air, the gills seem to laminate against the rock, just as crepe paper would if first held underwater before a rock was lifted out into the air from underneath it. However, underwater their gills behave like the crepe, flowing freely. They are performing their function as gills not suction cups. I find it hard to believe they evolved the way some think merely so they can make it more difficult for humans to pluck them from rocks in the atmosphere. How is it these mighty structures that defy our attempts to pry them from the rocks curiously fall off so easily when prodded for inspection a few seconds later in a tray or jostled in a container on the way home?
Even many scientific papers have encouraged these dubious beliefs so it's not just angler myth... And they go unchallenged... Thoughts?
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.ReplyGrannom vs Apple Caddis 7 Replies »
Love ths site.
While the Grannom Caddis and Apple Caddis are both from the Brachycentrus Genus, they are seperate "species". I believe much confusion is caused by some who refer to both as the "Grannom". Grannom (species: numerosus) is not the same color, nor does it hatch the same as the Apply Caddis (speicies: applachia). Pupa of the Grannom have a dirty olive, to dark olive body, with brown wing pads, and a brown shuck.They often hatch mid morning. The Apple Caddis Pupa is a light brighter olive, and a amber wing pad and amber to ginger shuck. Apple Caddis tend to hatch later in the afternoon. While size might be the same, the coloration of the adults have a completely different look. Apple Caddis adults have a very light colored wing, and a light (apple green body color). Grannom adults have a brownish wing with a body of dark olive, mixed with brown to black coloration. I have further noticed that the Grannom seem to hatch over much of the stream while Apple Caddis seem to hatch closer to shore. I'm just trying to clear up the problem of some calling both the Grannom, which leads to much confusion.Reply
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