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3. Mayfly help

Jason,
On May 26th, I was fishing the lower South Branch of the Oconto River. At about 3PM a hatch came off. The bottom was mostly sand and the shore was very silty. The water was 54 degrees. Some of the mayflies were flying over the water and then would hit the stream and appeared to be depositing eggs. Several mangled spinners were also on the stream but no trout were rising to them. www.wiflyfisher.com identified this mayfly as Siplonurus Alternatus. Do you agree? Thanks.
Doug

That's a Siphlonurus spinner, but I don't know which species.

Nevermind, I'm full of it.

Why Siphlonurus?

Paul...I think I might be with you here...Maybe Leptophlebia...We call it the "Borcher's Drake" or "Black Drake" on the Au Sable...I'll leave the final placement to the "Bug Boys" but the timing could be right for either bug. I can't tell how many tails the bug in the photo has...Leptophlebia has three I think and Siphlonurus two...(?)

If you google Leptophlebia there is a nice photo that looks close...I think the bug up north Michigan is cupida or was so if Mr McCafferty hasn't decided to rename it after himself. :)

Spence

Actually, I think Spence is right... it is Leptophlebia, not Siphlonurus. Siphlonurus has a distinctive pattern on the eyes that isn't present here. Leptophlebia is supposed to have a third tail, but it's probably just missing from this specimen or not visible in the picture.

Alaska is making me really rusty on my hatches!!

Spence I believe you've got it. Leptophlebia. cupida is the one I've seen in S NY. Very dark and noticeable tergites, the males with big dark eyes.

I've also seen Siphlonurus -quebecensis i believe it was -a very different looking beast, with those bi-colored eyes and fairly rotund somewhat flettened abdomen -like a fat Isonychia. Also with noticeable tergites. Bigger than Leptopphlebia too.

Both are slower water types, but the Siphlonurus takes the prize: The ones I found were in a shallow ditch in a hay field (!) -a good half mile from the nearest stream.

Spence -

So... You ARE a Bugmeister! Out of the closet now, huh?:)

I also agree it's a Leptophlebid male imago. Besides lacking the eye bands of the Siphlonuridae, the segment count of the hind tarsi preclude Heptageniidae (not enough of 'em). The segment ratio of the visible foretarsus is also a useful indicator. Other visual aids are the light rear legs and dark forelegs and overall look/shape of the body. This family seems to have issues with hanging on to their caudal filaments so you were right to ignore that.

Too bad the wings are covered, but it's most likely Leptophlebia cupida (Black Quill, Borcher Drake). It is possible to be nebulosa, johnsoni or perhaps even a few others. Out West we also have the species pacifica that lookes very similar. Perhaps a better look at the nasty bits and wings would help to know which species for sure but regardless, they're all Black Quills.

These are often hard to find as nymphs unless you scoop the slower margins with a net (cut banks are good) in late winter before they start to school up, which leads many to think they are far less important than they can actually be at times. There are pretty good populations of them in waters I fish often, the upper Williamson R. in Oregon for example.

Paul -
Wow, are you right about that! I dread high water that floods the marshes of the upper Williamson. You won't find a Gray Drake nymph anywhere near feeding fish, yet the duns and spinners fill the meadows. Very frustrating...


Regards,

Kurt

Really? I've always had a pretty easy time finding them when they're around, in both Wisconsin and New York. I do use a big kick-net, and I generally check slower margins as well as riffles, so maybe that's why.

Hi Jason,

I was adding the word "often" in front of "hard to find" as well as other comments you probably missed while responding as I was editing.:) Accidently posted it before I was ready and I can see how it could have been interpreted as meaning "always".

Still, I think a key point you raised is "when they are around". I'm curious to know when you were finding them easily because of the Leptophlebids habit of schooling prior to and during their seasonal emergence. I believe it is an example of a species that is probably under-sampled a lot if using kicknets or D nets during the spring. Perhaps a more important bug than many think?

My experience with them has taken place in beaver ponds, marshy areas of rivers, and slow undercuts. I haven't found it very easy finding many during their Spring emergence periods. I've occasionally observed their schools while fishing but never with a net in hand as luck would have it.

A side note: They sure swim better than literature says they do. Not Baetid speed maybe but still pretty good. At first glance you think you're seeing a school of tiny minnows. The upper Williamson is thick with them some seasons and actually provide better nymph fishing than the oft mentioned Gray Drake "super hatches" due to the latter's preference to migrate inland into flooded meadow grass or little trickles of irrigation ditches.

Regards,

Kurt

Interesting. I considered them 'rare' too, and suspected that habitat requirements were tight.

Looks like Leptophlebia to me. Can find them in droves in pools left from spring flooding. Most people don't go walking in the woods away from the stream and its pools! Yes, they are quite the swimmers. And the birds and other forest dwellers love them.

Jason -
Konchu -
Good stuff! Never found much evidence of them in freestone waters and often tough to find during their hatching period even in the waters mentioned above. Perhaps not always schooled up in a small section as I assumed, but in some isolated pool well back from the bank.

Regards,

Kurt

This mayfly had two tails. Does that change your answer?

No.

I was looking at images of Leptophlebia and it appears that some have a reduced central tail filament (cerci) -easily overlooked against the wrong background. Looks like cupida and nebulosa are this way. Maybe Roger (or others) can weigh in on species in your area. Also, the sand with silt shoreline indicate reduced flow in that stretch -Lepto habitat.

Your bug is NOT Ameletus -a very different looking creature. It's also NOT a Heptagniid, too feeble-legged and wrong body shape. It's not an Ephemerid (burrower) either.

After that, I think we'd be looking at a whole new species -or make that family. :)

Hey, looks like Roger may have already weighed in on this one:

http://www.flyfishingentomology.com/question%20re%20vermont%20mayfly.htm

I briefly posted about the middle tail condition, but then thought of exceptions, had regrets and promptly deleted it, so as not to invoke the ire of the ever-watchful tail-counters on this site (won't mention names). In general, though, I think you're right PaulRoberts. I use that in the field in my area here in Indiana. Just a technical point, though. Cerci are the lateral (side) filaments. The central one is a median filament. There are anatomical consistencies with other insects that make this so.

Thanks for that Luke. If I'm going to use exacting words like Cerci, I should certainly understand exactly what they mean.

Derdmann - This family is notorious for dropped tails in photos. You are as apt to see a photo with one tail or no tails at all as with two or all three. Also, some species have very delicate terminal filaments (central tail) with rather robust cerci to which they often cling. Tail counting is a good start, but can mislead. Without even looking at wings or tails, the dark forelegs and contrasting light middle and rears and solid eyes (lacking the Siphlonurid band) are traits immediatly noticable that clearly differentiate the two.

Luke - Enjoyed your radio interview! Especially your discussion on mosquitos. You had me chuckling to myself as I imagined the reaction of all those Detroit commuters listening in. Only a true Bugmeister would describe the little blood suckers as "good mothers". :) Good stuff.

Kurt.

Thanks everyone for weighing in. I am trying to learn what is in my streams and you all have been a big help. Now if I can just find a pattern to fool the trout...........

I will be back with more bug ID questions.

Doug