Review of 2019 and 2020 - Scorpionflies (Mecoptera) and Alderflies (Megaloptera)

SCORPIONFLIES (MECOPTERA)


Snow Flea Boreus hyemalis - None.  I've never seen a Snow Flea and they aren't often recorded in Norfolk.  Not sure there's a very high chance of finding one here but you never know...


Panorpa cognata - None.  I've never seen this species but there are a few widespread records from Norfolk so hopefully I'll bump into one before long.


Panorpa communis - Just 2 confirmed records of this species in 2019 and 2 in 2020, all from the Cathedral Meadows: a male on 21st June and a female on 29th June 2019 and 2 males on 3rd June 2020.  In addition a female on 3rd August 2019 was considered perhaps to be this species based on its wing pattern, but it did not allow capture to confirm.

female Panorpa communis, North Elmham Cathedral Meadows, 29th June 2019

male Panorpa communis, North Elmham Cathedral Meadows, 3rd June 2020

Panorpa germanica - 4 recorded at the meadows between 30th April and 25th May 2019 (the last to light) and one on Mull on 9th June.  Then in the autumn a small example to light at Swanton Great Wood on 27th August and another at the meadows on 3rd September.  In 2020 only recorded at the meadows where 4 between 9th and 27th May and 3 between 12th August and 8th September.  Quite a bit of variation in the wing pattern and a few showing distinctly yellow-tinged wings (especially but not exclusively involving the later individuals in August/September).

male Panorpa germanica, North Elmham Cathedral Meadows, 25th May 2019

male Panorpa germanica, Druimsornaig Cemetery, Mull, 9th June 2019

male Panorpa germanica, Swanton Great Wood, 27th August 2019 (showing genital capsule in second photo)

female Panorpa germanica, North Elmham Cathedral Meadows, 3rd September 2019 (showing genital plate in second photo)

male Panorpa germanica, North Elmham Cathedral Meadows, 9th May 2020 (showing genital capsule in second photo)

female Panorpa germanica, North Elmham Cathedral Meadows, 25th May 2020

female Panorpa germanica, North Elmham Cathedral Meadows, 27th May 2020

male Panorpa germanica, North Elmham Cathedral Meadows, 8th September 2020

I don't yet have enough data to draw any firm conclusions about flight periods, but tentatively it seems that both species have two generations and that germanica has a longer gap between them, the first one being earlier than communis and the second later.  But I need a bit more data before being remotely confident about this.

-----------------------------------

ALDERFLIES (MEGALOPTERA)


Sialis lutaria - As far as I know this is the only species of Alderfly that has been confirmed to occur in Norfolk although the other 2 species have been reported in the past (and subsequently considered unacceptable).  In any case it is the only species of Alderfly that I've seen so far.  I'd only identified one to species level before but found 4 individuals (all males) at the Cathedral Meadows in 2019.  Singles on 8th, 21st and 30th April were all found on Broom growing next to a dyke and I think the fourth on 15th May was in the same area.  Then in 2020 there were at least 3 Alderflies on the bridge over the dyke by the railway there on 24th April, one of which I potted off the metal railings and confirmed was as a male lutaria. 

Sialis lutaria, North Elmham Cathedral Meadows, 21st April 2019

Sialis lutaria, North Elmham Cathedral Meadows, 24th April 2020

-----------------------------------

SNAKEFLIES (RAPHIDIOPTERA)

I am not normally including orders in this review that I haven't recorded, but as for other Neuroptera and related orders I have included (or will be including) "nil returns" for species that I think have a reasonable chance of turning up round here, it seems fitting to at least mention the Snakeflies.  I've never seen any species of Snakefly and therefore won't cover them here in detail, but suffice to say for now that there are, I think, 4 species on the Norfolk list and judging from a recent Twitter conversation with Andy M and others it sounds like there's a strong possibility of finding at least one or two of them before too long.  I hope so anyway!

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