Artistic view of a Male Pteronarcys californica (Pteronarcyidae) (Giant Salmonfly) Stonefly Adult from the Gallatin River in Montana

Salmonflies
Pteronarcys californica

The giant Salmonflies of the Western mountains are legendary for their proclivity to elicit consistent dry-fly action and ferocious strikes.

This little pool in update New York is enjoyed by many tourists every day, and it still holds a few trout -- stockers mostly, but you can't complain about the setting!

From Mystery Creek # 62 in New York

Stream photos

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Ephemerella mucronata Mayfly Nymph Ephemerella mucronata Mayfly Nymph

Dorsal view of a Ephemerella mucronata (Ephemerellidae) Mayfly Nymph from the Yakima River in Washington

This is an interesting one. Following the keys in Merritt R.W., Cummins, K.W., and Berg, M.B. (2019) and Jacobus et al. (2014), it keys clearly to Ephemerella. Jacobus et al provide a key to species, but some of the characteristics are tricky to interpret without illustrations. If I didn't make any mistakes, this one keys to Ephemerella mucronata, which has not previously been reported any closer to here than Montana and Alberta. The main character seems to fit well: "Abdominal terga with prominent, paired, subparallel, spiculate ridges." Several illustrations or descriptions of this holarctic species from the US and Europe seem to match, including the body length, tarsal claws and denticles, labial palp, and gill shapes. These sources include including Richard Allen's original description of this species in North America under the now-defunct name E. moffatae in Allen RK (1977) and the figures in this description of the species in Italy.

17 Recently Added Photos

27" brown trout, my largest ever. It was the sub-dominant fish in its pool. After this, I hooked the bigger one, but I couldn't land it.

Troutnut is a project started in 2003 by salmonid ecologist Jason "Troutnut" Neuswanger to help anglers and fly tyers unabashedly embrace the entomological side of the sport. Learn more about Troutnut or support the project for an enhanced experience here.

i posted this in the forum, but...

This topic is about the Insect Order Ephemeroptera

Mayflies may be the most important insects for trout anglers to understand. They are an ancient order of insects, famous outside the fly-fishing world for their fragile beauty and short adult lifespan, often a single day to mate and die. The mayfly's poignant drama attracts poets and anglers alike, but anglers make the most of it.

Mayflies live more than 99% of their lives as nymphs on the river or lake bottom, filling many crucial roles in freshwater ecosystems as they feed and grow. They eventually emerge from the water as winged sub-adults called "subimagos" by scientists and "duns" by anglers. Duns evolved to be good at escaping the water, with a hydrophobic surface and hardy build, but they are clumsy fliers. Within a day or two they molt one last time into "imagos" or "spinners," the mature adults, a transformation captured in this photo series of a dun molting into a spinner. They have longer legs and tails, and sleeker, more lightweight bodies, giving them the airborne speed, agility, and long grasp they need for their midair mating rituals. They are usually darker than the duns and have shinier, more transparent wings. They die within minutes or hours after mating.

Example specimens

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Male Epeorus albertae (Pink Lady) Mayfly Spinner

Lateral view of a Male Epeorus albertae (Heptageniidae) (Pink Lady) Mayfly Spinner from the North Fork Stillaguamish River in Washington

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Male Epeorus deceptivus Mayfly Dun

Artistic view of a Male Epeorus deceptivus (Heptageniidae) Mayfly Dun from the South Fork Sauk River in Washington

The lack of a darkened humeral crossvein rules out Epeorus albertae and Epeorus dulciana. The lack of a dark macula on the forefemora rules out Epeorus longimanus. The small size rules out Epeorus grandis and Epeorus permagnus. That leaves as the only possibility known in Washington state Epeorus deceptivus. It is a small species, although not reportedly quite as small as this specimen. I couldn't find anything in the species description in Traver (1935) to definitively confirm or rule out the species ID, given that I don't have the preserved specimen to check under a microscope, but it has to be either deceptivus or something not yet reported in Washington. It was collected at the same time as a similar-sized female dun.

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Female Acentrella turbida (Tiny Blue-Winged Olive) Mayfly Spinner

Lateral view of a Female Acentrella turbida (Baetidae) (Tiny Blue-Winged Olive) Mayfly Spinner from the Middle Fork Snoqualmie River in Washington

Rckrego
Princeton, NJ

Posts: 2

Rckrego on Apr 18, 2007April 18th, 2007, 7:32 am EDT

What's the difference between olives and bwo's? I've been told that there is a family or genus difference, and accordingly there are size and color differences. Is there anything definitive about this? Do the nymphs act differently? Are the hatches at different times of the year? Are the wings of olives really different from the wings of BWO's? thanks.

Here fishy, fishy, fishy...

Troutnut

Administrator
Bellevue, WA

Posts: 2758

Troutnut on Apr 18, 2007April 18th, 2007, 8:03 am EDT

Hey,

I hope you don't mind I deleted the other topic -- it'll get confusing if we have people answering your question in two places.

The short answer is that you just can't get this technical about common names like olives and BWOs. BWOs usually don't have blue wings anyway, and lots of them aren't even olive. People slap those labels on just about anything green or small except for inchworms. See one of my articles on this site for more about the common name confusion.

When you start wondering about details and distinctions like this, that's the time to take the plunge into scientific names. Your questions can't really be answered for "BWOs" or "Olives", but you can learn all kinds of interesting details about Baetis or Drunella. :)

Jason Neuswanger, Ph.D.
Troutnut and salmonid ecologist