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Siphlonurus sp.

4K views 13 replies 4 participants last post by  Whingeing pom 
#1 · (Edited)
This is one of the largest upwinged flies of Europe and Britain. Fly fishermen call it Large Summer Dun/Spinner. This insect is not well known as a Green Drake or Blue Winged Olive, but it is present in decent numbers in many lakes and rivers. The nymphs are agile darters and can be found in slow parts of the rivers and near banks of the lakes. They crawl ashore to hatch. They are interesting to flyfishermen because they do it just a few centimeters outside of the water, and many duns fall in. Fish easily grab this handsome source of food. Later, as the spinner, Siphlonurus female come back to lay eggs dipping into the water, again in fish-eye focus.



Large number of Siphlonurus nymph preparing to hatch



The hatch is on!



Dun
 
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#5 · (Edited)
Siphlonurus is very large, just as Green Drake (E. danica). I picture these in East Europe / Serbia (where i am from). According to John Goddard (Trout Flies Of Britain And Europe), Pat o' Railly (Matching The Hatch) etc. same or similar species live in Britain and rest of continent.
 
#11 ·
#13 ·
Hi', Mixmaster, and All.
Thanks for the pictures. We have three species of Siphlonurus :-- alternatus, armatus and lacustris.
I can't honestly say that I have seen any of the three and identified them, but I did see a big upwing on the fells once or twice when I was researching the tarns in the 1990s. Just checked an adult Ephemeroptera key, and S. lacustris is found chiefly in lakes, slow-flowing sections of rivers, and ponds at high altitudes. Well, we have plenty high ponds where I live. Red Tarn lies at 2356ft. Also saw a big silvery-white sedge fly one day on Scandale Tarn, across from Red Screes, above Kirkstone Pass. Maybe I saw S. lacustris -- I'll never know.
A fly that I have looked for occasionally, but haven't found, is the missing Medium Olive Dun -- the Baetis tenax -- which was found on the high fells by T T Macan. I can't understand why his fly is not in the list for the British Ephemeroptera. If I get up on the fells again, I would like nothing better than to find a few agile darter larvae and, hopefully, have one or more identified as the missing fly/larva from the list. T T Macan deserves that, IMHO.
Just remembered, because the Siphlonuridae are so big, they are sometimes caled, Summer Mayfly. The Summer in the title must have been chosen because the first two, alphabetically, have a flight period from May to August, while lacustris is around through September.
I wish I had been taught Latin at school -- Lacustris is a reference to lakes.
Just as a point of interest, T T Macan identified 25 of the known 46 Ephemeroptera, in the Lake District at the time he wrote 'Life In Lakes And Rivers', had he included the Eden valley in his searches, he would have found more. He did rather well with sedges, 108 out 188 known species and 24 of the known 31 stoneflies. His book first appeared in 1951, the year of the first O-Levels, when I took mine.
Dr Macan also reported the spectacle of Corixae flying into small peat pools at nearly 2500ft above sea level -- 23 were caught in the space of 45 minutes. The catch consisted largely of a species very rare in the Lake District. If they had come from outside the area, they must have flown six miles at the very least. Now there's a thing!! Cheers, TerryC
 
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