Early Mayfly?

Marilinda · #1 (**permalink**) 22-03-2011, 10:46 AM

I saw this Mayfly resting on a branch in woodland on 15th March. I only managed to take one photo before it flew off. I have not been able to identify it. Can anyone help please?
Many thanks
Marilinda

Dogghound · #2 (**permalink**) 22-03-2011, 11:06 AM

Its one of the Baetidae, I would need a closer look to ID it. Mayflies are not restricted to May and different species can be found around the year.

Endrick · #3 (**permalink**) 22-03-2011, 11:34 AM

That's a Large Dark Olive - Baetis rhodani. They're by far the most common upwing at this time of year. I was watching them hatching in good numbers on the upper River Clyde last week. At this time of year you will mainly see them around lunchtime. They even hatch in the middle of winter on mild sunny days.

Malcolm Banks · #4 (**permalink**) 23-03-2011, 10:20 PM

Sorry to piggyback onto this thread, but since expert glances had already been turned to it, it seemed a good place to add my observation.
A couple of days ago on a warm late morning, I saw what I took to be a Mayfly take off from the edge of the pond. It was gone in a trice, but I got the impression it was 2.5-3cm long, including the two long tail filaments, pale straw coloured). I knew that Mayflies had a range of emerging periods from April to the summer months, but didn't think they emerged as early as March. When I tried Googling Mayflies in March, all I got was the March Brown (Rhithrogena morrisoni) - but this is dark (maybe they darken with age?) but more importantly, they are apparently only found in large rivers.
Can anyone help me believe I wasn't seeing things, and that there are other Mayflies that emerge from a pond in March?

M

Endrick · #5 (**permalink**) 24-03-2011, 11:41 AM

First an update on terms!

In the UK the "mayfly" traditionally referred to just two species: Ephemera Danica and Ephemera Vulgata (actually there are another couple but they are much rarer). These were also known as the "drakes".

Other members of the ephemeroptera were known as olives or upwings. However Americanisms abound and the Americans call the ephemeroptera "mayflies" and this term has started to creep into common usage in the UK.

You can actually find upwings on any day of the year. By far the most common in winter and spring is the Large Dark Olive (Baetis Rhodani) which I have seen hatching in Scotland in January. From about now for the next few weeks there will also be hatches of the March Brown which is a big fat bodied upwing and can only be confused with a few others: the large brook dun and the Turkey Dun being notable but these are much rarer and don't hatch in the thousands - as March Browns do. They also hatch a bit later although there may be some overlap.

There are a number of useful books on the insects of rivers and lochs. These are targeted mainly at fly fishermen - I'm one myself - and tend to centre on the upwings (ephemeroptera), caddis (trichoptera), true flies (diptera) and stoneflies (plecoptera). A useful book is John Goddards Waterside Guide although his descriptions of hatch times and distribution isn't great.

Best Regards
Malcolm

Marilinda · #6 (**permalink**) 24-03-2011, 09:31 PM

Many thanks, this is all very interesting. There is a small stream running through the wood where I saw the Mayfly. It was about 25metres away from the water and caught my attention because I thought it was a dead leaf at first fluttering in the breeze - the wings were opaque. I did try Google but couldn't find much.
Marilinda