Mayfly magic - out with the old skin and in with the new

On Saturday afternoon I joined Dave and Matthew Casey on one of Matthew's patches that was a site for Large Red-belted Clearwings.  It's a bit early but Dave has a pheremone lure and we thought it worth a shot.  We didn't succeed with the Clearwings but saw a nice variety of inverts, and it was good to meet Matthew again - and also really nice to meet James Lowen for the first time, who lives nearby and turned up later with his daughter.

Dave and Matthew had already found a Marsh Pug and some Little Long-horns Cauchas fibulella before I arrived, and other Long-horns included a couple of Meadow Long-horns Cauchas rufimitrella.

Little Long-horn Cauchas fibulella, New Costessey, 28th May

Other moths included Common Nettle-tap Anthophila fabriciana, Thistle Bell Epiblema scutulana, Grey Gorse Piercer Cydia ulicetana, Red Twin-spot Carpet and Common Carpet.  Butterflies included Holly Blue and Speckled Wood, and Damseflies included Azure and Blue-tailed.

Azure Damselfly, New Costessey, 28th May

There were lots of Mayflies along the stream.  They looked distinctive but to be sure of getting an ID I took one home in a pot to examine with the key to hand.  It proved to be a Green Drake Ephemera danica but the more interesting thing was that it shed its skin while in my pot.  I'd already photographed it when I looked back at the pot and at first thought there was a second, dead, Mayfly in the pot.  How could that be, I pondered, before realising that it was in fact an empty skin.  The new iteration of Mayfly didn't look vastly different from the first, but the body was brighter and paler, the wings seemed paler and more strongly marked and the tail was longer.  I don't know much about Mayflies yet, but learned something new here.  Firstly I hadn't realised that the change from sub-imago to imago (adult) involved shedding its skin and secondly, when I read up on that the text seemed to imply that the sub-imago just rests before moulting into an imago, yet mine was definitely captured in flight.

Green Drake Ephemera danica, New Costessey, 28th May - the sub-imago, its shed skin and the resulting imago

This Alder Fly turned out to be Sialis lutaria.  There are 3 species of Alder Fly in the UK and you have to examine their genitalia to sort them out.  They don't need a full dissection but I must admit I found it a bit tricky matching my specimen to the diagrams in the key.  Got there in the end though, I think.

Alder Fly Sialis lutaria (male, gen det), New Costessey, 28th May

Other inverts of note were Dock Bug, Red-headed Cardinal (beetle) and Green Nettle Weevil Phyllobius pomaceus. Snails included a Strawberry Snail Trochulus striolatus and Dave pointed out what turned out to be my first identified Amber Snail Succinea putris.

Dock Bug, New Costessey, 28th May

 Green Nettle Weevil Phyllobius pomaceus, New Costessey, 28th May

Amber Snail Succinea putris, New Costessey, 28th May