Meeting Sally…

Wednesday 21st February 2024

…a blog written by Sarah Hawkes. Buglife’s Natur am Byth! Scarce Yellow Sally Project Officer.

Scarce Yellow Sally is a stonefly measuring around 14-20mm long that was thought to be extinct in the UK following 22 years during which no sightings were made at all. However, in 2017 a survey by John Davy-Bowker re-discovered small populations in the River Dee in East Wales.

Erica McAlister (left) & Sarah Hawkes (right) © Dr Will Hawkes
Erica McAlister (left) & Sarah Hawkes (right) © Dr Will Hawkes

I am Sarah Hawkes, the newly appointed Project Officer for the Scarce Yellow Sally.  I’m very much hoping to get a chance to see the live animal during our Buglife surveys later in March and looking forward to bringing Scarce Sally to greater public attention, helping highlight the importance of this critically endangered species (known in the UK only from the River Dee in Wales) to a wide audience.  To try and understand more, I wanted to find out about the origins of our knowledge about the Scarce Yellow Sally (Isogenus nubecula) whose ‘common’ name began as the Rare Medium Stonefly.

Let me introduce two of the principal characters in Sally’s scientific history: Edward Newman, who first described Isogenus nubecula for science in 1833 and the specimen he described (the holotype) which is in the London Natural History Museum.

Meet Edward Newman

Edward Newman at 25 was a founder member of the Entomological Club in 1826. He soon became editor of the first Entomological Journal and in 1833, the year in which he described Isogenus nebucula for science for the first time, he also became one of the founding members of what is now the Royal Entomological Society, and a Fellow of the Linnean Society.

Edward Newman Photograph by Maull & Polyblank Credit – Wellcome Collection CC BY

Edward was a Quaker, born in Hampstead near London (in those days not yet a part of London).  A forthright and determined character, he was enthusiastic about making insects interesting to the general public.  This is an enthusiasm we in Buglife can easily relate to!  His strategy was often to use verse to introduce quite complicated scientific concepts in a digestible form to children.  Reading the rhythm of his verse, he was clearly heavily influenced by Hiawatha’s poems.

Here is Edward Newman’s introduction to the Stonefly family – one of many verse introductions he wrote about insect families – which he published in his collection The Insect Hunters and other poems in 1861:

“Lastly, come the heavy Stoneflies,
Known in Science as Perlina,
Very like domestic crickets.
But are river loving insects.
Their heads rather broad and flattened,
Their eyes small, and round, and distant,
Fore wings flat, and hind wings folded,
Larger, broader than the fore wings.
Larvae more than half aquatic.
Nimbly swimming in the water.
Nimbly diving in the water,
Nimbly running on the bottom,
Hiding under little pebbles,
Often coming out, and creeping
On the bank and on the grasses.
Crawling up the trunks of willows,
Hiding in the cracks and crannies.
When the pupa is quite ready
To become a winged imago,
Then it grasps the bark of willows,
Or the rounded stems of rushes.
Or the pliant blades of grasses.
By its hooked claws firmly anchored.
Then the back splits open lengthwise,
And the perfect fly emerges,
Flying softly o’er the streamlet,
To become the prey of fishes.
Seeing this, the wily angler
Makes an imitation Stonefly,
Which, the fatal hook concealing,
Is appended to the horsehair,
And dropped softly on the surface
Of the bright and dimpled river.
And there, scarce a moment floating,
Tempts the lurking trout or grayling
Irresistibly to seize it.”

Having discovered Edward Newman, the entomologist, it was time for me to meet the animal he had described for science in 1833.

Meeting Sally

Dan Hall, Dr George McGavin & Sarah © Dr Will Hawkes
Dan Hall, Dr George McGavin & Sarah © Dr Will Hawkes

I’m up at 4am to catch the train at 6:03.  The dogs look sad as I go out of the door without them and head off to the London Natural History Museum to see the holotype of Isogenus nebucula, the ‘Scarce Yellow Sally’ I want to meet.

I get to Birmingham New Street Station and negotiate the terrible signage between there and Birmingham Moor Street Station.  The next train is slow but I arrive at the Natural History Museum (NHM) almost on time and meet the other two excited people who are joining me for my trip burrowing into the collection where I’ll meet the Scarce Yellow Sally for the first time with the help of Dan Hall, Assistant curator of Small Orders.

At first Diptera and their amazing stories, told by Dr Erica McAllister, Dr George McGavin and Dr Will Hawkes, are all consuming and it is hard to leave, but just before lunch we move at last to the Small Orders, which have their own special room, (much smaller than the Diptera collection room which is in turn far, far smaller than the Beetle room).

Scarce Yellow Sally’s drawer is already out and waiting for us and there is the stonefly I have come to see!

Scarce Yellow Sally holotype © Dr George McGavin
Scarce Yellow Sally holotype © Dr George McGavin

This, the holotype specimen, was caught on the banks of the Severn in Worcester by A. Burlingham, (probably this was S. Alexander Burlingham, from another Quaker family, living in Worcester at the time).  Sally the Holotype is an adult stonefly.  Nonetheless, the majority of this insect’s life was spent as a larva living not only under water, but in fast flowing rivers over a metre in depth, under and between the riverbed cobbles and gravels.  It is not an animal most of us will ever come across during its larval stages!

At some time during Sally’s life as a specimen in the Natural History Museum drawer ‘she’ had a rather dramatic accident to her abdomen and has been stuck back together with glue.  Also, the pin holding this precious cargo is corroding and you can see green verdigris spreading from the metal.  The label put onto the pin in 1833 has become almost black but despite all these problems all is not lost.  The museum has been working on digitizing the collection, taking photos of each specimen with its labelling (from 6 angles), deciphering the writing where it is difficult, transcribing all the data relating to each specimen in every drawer, onto digital records that will be available for researchers worldwide.  It will even be possible, using new ‘washing’ techniques, to extract DNA from this specimen despite its great age.

Erica McAlister, George McGavin, Dan Hall, Sarah Hawkes and Will Hawkes at NHM London for Diptera Collections Tour - Jan 24
Erica McAlister, George McGavin, Dan Hall, Sarah Hawkes and Will Hawkes at NHM London for Diptera Collections Tour

So far, on my own journey with the Scarce Yellow Sally, this dried but extremely special little 191 year old specimen is the closest I have come to the real living animal. It has been an inspiring experience.

This little Sally’s descendants are now truly scarce and at risk of extinction, but with Buglife’s help within the Natur am Byth project, it may just be possible to change that.  If we can, it will make a difference to the future of all riverflies on the Welsh Dee and elsewhere in the world.

During March our surveys of the river will begin.  We’ll be assessing the current state of the Isogenus nubecula population in the Dee and the conditions of the river it lives in.

I will be talking about that in my next blog!

Natur am Byth! is Wales’ flagship conservation project.

Made up of a partnership of nine environmental charities and Natural Resources Wales the programme is taking action for endangered species; building connections with Welsh communities and their natural heritage.

Buglife is leading on two projects: Swansea Bay – Coasts, Commons & Communities & the Scarce Yellow Sally (Isogenus nubecula) single species project.