Bit of Help and Advice

danielp

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Hi guys and gals

I am in the process of improving my entomology knowledge and have begun to collate the approximate hatch dates for some of the major river bugs we lot are interested in. To that point I have put together a small table where the dark shaded areas indicate the most abundant hatches and the lighter grey are less abundant. Are there any of these that are just plain wrong or need a bit of tweaking? I appreciate hatch times will vary slightly with location so please bear in mind these are geared towards Southern freestone rivers.

With the locale in mind are there any species which would warrant being included which are currently absent?



Updated flight times of sedges, BWOs and Yellow Mays


Many thanks in advance
Dan
 
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cmscotfly_92

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I understand the table is based on your local area, nevertheless, I'm surprised you don't still have abundant hatches of blue winged olives later in the year in your area. Albeit they could be there and they just haven't been identified at that time of the year. Even as temperatures drop a good bit in autumn in central scotland we still get loads coming off the rivers and it wasn't until last year I learned that Grayling favour these when the trout start to slow their feed and move upstream and into the tributaries. There were great numbers on my local river yesterday, but it was mostly baetidae. "Aren't BWO's from the baetidae genus?" After a lot of research I've discovered the answer to that is no, and many anglers are confused over the matter, however, true full time entomologists have determined they are not from the same genus as most other olives and are the only one of their kind in the UK. Making them a particularly special little fly, and good eating too so it seems.
 

oldbull

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cmsscotfly is right, I've seen some big hatches of BWO towards the end of October on the River Tawe.

Ray
 

jada0406

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Hi', Daniel,
An important aid in identification of upwinged flies is the number of tail 'whisks'. All the baetidae have 2. Some confusion may arise from the larvae of all have 3 setae.

A slight digression; the larvae of upwinged flies are true nymphs, so are those of stoneflies, damsels and dragonflies. The basis for this collective title of 'nymphs' is partly that the bodies of the larvae resemble those of their adults -- especially the stonefly 'creepers' which look very like wingless adults. Sedges and midges differ in that they have a pupal stage --so, larva, pupa, imago. There is a marked difference between upwinged fly development and that of the other species that have nymphs --- the larvae emerge as a sub-imagoes/sub-imagines, which become imagoes/imagines. Or, duns become spinners.

Back to your spreadsheet (well done), you can certainly extend the flight period of BWO as the lads have suggested, and that of sedges, which are quite commonly seen in October, less so in November, in some parts of the UK. The definite flight period of YMay can also be extended into late summer/early autumn, October in some areas. Cheers, jadaTC
 

danielp

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Many thanks for all the advice guys it was exactly what I am after. I will make the changes and update the table.

Are there any species you can think of that are important that I have missed altogether? I apologise for not breaking the sedges down in to more than just grannom and everything else, but I have no clue how to separate the other species. I think I may add in some stoneflies and possibly alders although I have yet to see them actually on the river and not just in the air.

Jada- I actually did an insect biology course at Uni (feels like an age ago now) and it is what has spurred my love of the little buggers. I need to get much better at telling them all apart though which is the drive for me to put this table together. Next step will be breaking them up in to family groups and learning the features.

Dan
 

diawl bach

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Good idea that Dan.

I'd put hawthorn flies on the list, the trout can get very fixated on these April to May terrestrials - black hopper job. I've only seen one so far this year but it's been an odd spring all round as the hawthorn trees have only been in bloom for a week or so.
Currently waiting for the sun to drop a bit before getting down to the Taff, it looks in very good nick today.
 

jada0406

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Hi', Dan, if you are interested only in upwinged flies and sedges, your sheet looks OK, but the key that I once bought from the Freshwater Biological Association for identification of the adult upwinged flies has a more comprehensive list.
It's a paperback, "A Key to the Adults of the British Ephemeroptera." by professors J. M. Elliott and U. H. Humpesch.

A handy little coloured guide, "A Guide to the Adult Caddis Flies or Sedge Flies", by Dr Peter Barnard and Emma Ross, may be available from:--

FSC Publications, The Annexe, Preston Montford, Shrewsbury, Shropshire,
SY4 1DU. ---- 0845 345 4072 Cheers, TerryC
 

danielp

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Cheers guys,

DB I will add hawthorns to the list. Have not seen any yet but they must be about soon!

Jada, I would like to add some more varied species to the list I am just pretty rubbish at identifying them lol. I will have a look at the publications you suggest!
 

BENDINO

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I would add hawthorn & stoneflies Dan - plenty about on the Tawe & Usk right now.

Rob
 
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