Please identify this mayfly

Tedlyflyfisher · Nov 21, 2023

Guys, I took this photo several years back. A mayfly on a window near the Boise river. A smaller dude, I kinda thought it must have been a trico spinner, but I read they have 3 tails. Can any of you identify this for me? TIA.

Scottp · Nov 21, 2023

Paraleptophlebia, I’d guess.

Regards,
Scott

Triggw · Nov 21, 2023

Small, grey mayfly. Fish small, grey fly.

James St. Clair · Nov 21, 2023

I would say family Baetidae (I call them Baetis, many call them Blue Winged Olives). Not sure on the Genus, but someone more qualified may be able to tell from the picture.

As a side note, I think Blue Winged Olive being used for Baetidae is misleading, as I believe the original "Blue Winged Olive" common name was used to identify some mayflies from the Ephemerellidae family. Additionally, while the Baetidae in my area are in most cases light Olive, a recent trip to the Green River in Utah showed me that the Baetidae in that area are mostly gray.

Like @Triggw said, fish a size 20 or 22 parachute with some white microfibbets, a light gray/cream body, dark thorax, and light dun Hackle.

Scottp · Nov 22, 2023

Paraleptophlebia mollis male spinner

Fly Fishing Gallery

www.riseformsflyfishing.com

Used to run into them fishing Big Hunting Creek in Maryland back in the 90’s; mostly the duns, #16-18 (western ones smaller?), not the spinners like the pic you posted. Never hit a heavy hatch but the fish seemed to like them; think I used a grey bodied Hairwing Dun.

Regards,
Scott

James St. Clair · Nov 22, 2023

Scottp said:
Paraleptophlebia mollis male spinner

Fly Fishing Gallery

www.riseformsflyfishing.com

Used to run into them fishing Big Hunting Creek in Maryland back in the 90’s; mostly the duns, #16-18 (western ones smaller?), not the spinners like the pic you posted. Never hit a heavy hatch but the fish seemed to like them; think I used a grey bodied Hairwing Dun.

Regards,
Scott

Scott -

That picture sure makes it look like you nailed it, they look identical!

Definitely not trying to start an argument, but now you got my curiosity going. I notice the picture from that link is from PA, and I don't see that species being present in the Northwest in any of the texts. I also think it's possible that the picture from your link is incorrectly identified. I believe that to be a Baetidae as well. From Merrit and Cummins key, family Leptophlebidae have 3 tails (cerci).

Paging @Taxon and @Mark Melton.

John Svahn · Nov 22, 2023

Scott, I too fished big hunting creek in the 90s. I am a fighting terrapin, did my major in fisheries management and my minor on aquatic ent in fishing creek, right next door!

Matt B · Nov 22, 2023

Does the pictured spinner have a malformed third (middle) tail? What’s that little loop thing there?

James St. Clair · Nov 22, 2023

Matt B said:
Does the pictured spinner have a malformed third (middle) tail? What’s that little loop thing there?

Those are his penes...his sex organs for reproduction.

Matt B · Nov 22, 2023

James St. Clair said:
Those are his penes...his sex organs for reproduction.

Thanks! But—Now I feel slightly embarrassed for scoping the li’l dudes genitalia.

Scottp · Nov 22, 2023

James,

Appreciate your take on the bug in question. I’d be curious to hear what the bug guys have to say, too.

Regards,
Scott

kmudgn · Nov 22, 2023

Purple Haze will work for that bug

Tedlyflyfisher · Nov 22, 2023

Great replies, thanks guys! James, I was leaning toward bwo’s as well, but the coloration just didn’t seem right.

Scott, that pic of the paraleptophlebia sure seems to be right on the money.
I encounter them in just a few waters in my area (SW Idaho), but see these “Mahogany Duns” in the fall, whereas I believe I took this photo in the summer. (I could be wrong, I took this photo years ago).

Paraleptophlebia | Idaho Fish and Game

idfg.idaho.gov

Also, the (excellent) book Western Mayfly Hatches by Hafele and Hughes states that Mahogany Duns have 3 tails, not 2 as in my photo.

So, for me, the jury is still out …

Mark Melton · Nov 22, 2023

The id of the mayfly as Paraleptophlebia is incorrect because Paraleptophlebia has three tails as an adult not two as shown in the photo. The photo doesen't appear to show one broken off either. My guess is Baetidae, possibly an Anafroptilum species. Idaho doesn't list any Anafroptilum species but Washington, Oregon and Montana do.
https://bugguide.net/node/view/694707/bgimage

Taxon · Nov 22, 2023

Mark Melton said:
Idaho doesn't list any Anafroptilum species but Washington, Oregon and Montana do.

Hi Mark-

I believe there is actually at least one Anafroptilum species present in Idaho. Please see Anafroptilum bifurcatum.

Mark Melton · Nov 22, 2023

Taxon said:
Hi Mark-

I believe there is actually at least one Anafroptilum species present in Idaho. Please see Anafroptilum bifurcatum.

Yeah, apparently there is. I was going by Idaho's Fish and Game guidebook which says there are none in the state. https://idfg.idaho.gov/species/taxa/2011420
Incidentally, your map shows none in Montana. Apparently they have two species of Anafroptilum.

A Mayfly - Montana Field Guide

fieldguide.mt.gov

A Mayfly - Montana Field Guide

fieldguide.mt.gov

Taxon · Nov 22, 2023

Mark Melton said:
Incidently, your map shows none in Montana. Aparently they have two species of Anafroptilum.

Thanks for the heads up, Mark. My distribution maps for both Anafroptilum bifurcatum and Anafroptilum conturbatum have now been updated.

Zak · Nov 22, 2023

These exchanges between @Mark Melton and @Taxon are so informative! Thanks, Guys!

RCF · Nov 22, 2023

We all get the best and updated information when @Taxon and @Mark Melton interact with each other respectively each adding to other's knowledge ---> win - win - win!