Saturday 30 October 2021

Double County First!

Finding Choreutis nemorana

Fig-tree Skeletonizer - Choreutis nemorana

Back in 2014, a new moth to Britain was found in Hyde Park,  London.  The somewhat alarming name of this diminutive moth is the Fig-tree SkeletonizerChoreutis nemorana. Visions of leafless, skeletal Fig trees left dying across the land are totally misguided as the larvae of this adventive species do little more than chew a few holes in the leaves! 

News of this new moth reached me via a friend of mine with a particular interest in the early stages of moths. He told our group to look out for the tell-tale signs on Fig trees as "you never know". Shortly after, I found a potted Fig, around a metre tall,  in the grounds of my children's school here in Lowestoft. It became a daily habit to idly look over the leaves of this tree,  just in case some of these tiny moths decided to make the 130 mile journey from Hyde Park!

Years passed and, needless-to-say, I never found evidence of the moth on the school tree.  As our boys progressed through school,  I didn't see the potted Fig for months on end and thoughts of finding the moth were long-forgotten.

Fast forward to October 10th 2021. I met up with members of the Suffolk Moth Group for a leaf mine session in Lowestoft. I joked with the County Recorder that after a county first in 2019 and another in 2020 I was running out of time to find one this year.  The very next day,  Sarah and I were out walking when we happened to pass under an overhanging Fig tree which was growing in the gardens of an old house in Kirkley. Something caught my eye and I can only describe it as a 'light bulb moment"... 

A 'moth eaten' Fig leaf

A close inspection of the leaves revealed silken webs over the damaged parts of the leaf and after checking several leaves I found a larva. Having recently found the Apple-leaf SkeletonizerChoreutis pariana on a local Apple tree I was pretty confident I'd found its Fig-munching cousin. 

The First Caterpillar

Sarah then spotted something different on a higher leaf; a neat curled leaf which looked like it might have something inside...

Rolled Leaf

I later found out that Choreutis nemorana has an alternative common name, the Fig Leaf Roller.  I bagged the leaf with the larva on and took a couple of rolled leaves to study at home later.  I loaded up the Suffolk Moths website on my phone but couldn't find an entry for it. I tried the Norfolk Moths site but again, no entry.  I realised that I might just have found myself another county first...

Back at Home I tried to find out as much information on Choreutis nemorana as possible but there was almost nothing in any of my guide books and internet search results were sketchy at best.  I found an article written about the original discovery in Hyde Park from 2014 but almost nothing else from the UK.  I turned my attention to social media and found a few entries on Facebook and Twitter showing that the moth had apparently been found widely across the London area, a couple of locations in Kent and a single record of an adult trapped at light in Essex this year (2021).  

I took some reference photos of what I had collected and sent them to the Suffolk County Moth Recorder, Neil Sherman, but with no previous experience of this species, he wanted to see an adult to be sure...

Silken web over the leaves

Skeletonised Fig leaf

Another rolled leaf

Cocoon inside the rolled leaf

Extracted pupa

I messaged a mothing friend of mine, Jonathan Newman, asking him if he'd seen Choreutis nemorana or knew anything about it.  He replied by saying that he had never seen it and would love to rear some.  With only a couple of cocoons and no guarantee of them successfully emerging, I managed to persuade Sarah to return to the Fig tree the following day. Now picture the scene... two adults, plastic bags in hand, picking our way through the leaves of an over-hanging Fig tree, searching for rolled leaves and caterpillars.  It might seem weird to most people but for me and my long-suffering wife this is quite normal behaviour!  I was fully prepared to explain our afternoon activity to anyone who cared to question what we were doing but the passers-by simply ignored us.  How odd!

I sent a few cocoons to Jonathan Newman who has lots of experience rearing micro moths and I kept some for myself.  Then it was just a case of doing nothing and waiting for them to emerge.  However, doing nothing isn't what I wanted to do;  I had a bright idea of searching for the moth in Norfolk too.  Without actually driving to a Norfolk town and searching for Fig trees I decided to use Google Street Maps.  I picked the first small town across the border, Caister-on-Sea and did a virtual walk around looking for Fig trees.  After a couple of hours I struck gold; a large Fig overhanging the pavement along the main road.  Although i couldn't see enough detail on the leaves to know if the moth was present, I felt that it was worth a look at least.  That weekend we decided to have a family outing to Caister beach and lunch at Poppylands in Horsey.  After playtime on the beach we drove a little way up the road where  I parked up and walked around the corner to check for signs of Choreutis nemorana on the Fig.  It took all of 2 seconds to see that the tree was covered in skeletonised leaves and with the help of my eldest son, we bagged some more rolled leaves as evidence to send to the Norfolk County Recorder. 

The Caister Fig

With the first records for both Suffolk and Norfolk within 5 days, all I could do now was wait for an adult to emerge so that I could make the finds public.  Every day, myself and Jonathan exchanged messages but neither of us had an adult emerge until October 16th... I was out with the family on a shopping trip when my phone pinged with a message from Jonathan; "congratulations I'm a step-daddy" and the following photo:

Suffolk's first recorded adult Choreutis nemorana (J.Newman)

With photo evidence of an adult I was able to put the news out on our Suffolk Moths WhatsApp group followed by the Suffolk and Norfolk moth groups on Facebook.  Within a couple of hours of putting the news out, I was receiving reports of likely C.nemorana from up and down the East Anglian coast from Hollesley up to Winterton-on-Sea!  When I got home from shopping a found that I too had an adult, this time from the Norfolk batch.  Within a couple of days we had several adults between us and it was interesting to see how much variation there was between individuals.  They were fascinating to watch; they scurried about on the leaves and only flew in short bursts from leaf to leaf. Their resting posture is similar to that of the Apple-leaf Skeletonizer, Choreutis pariana, with head down and bum up in the air!

Distinctive resting posture

White face and legs

Scurrying about on the leaf

So what about that small potted Fig in the school playground?  I couldn't remember seeing it for moths if not longer.  I had forgotten to look for it the previous week when picking up one of our mindees (we are childminders) so on October 20th I made a beeline to the corner of the playground where I last saw it.  It took some finding as the potted tree had been moved next to a hedge where it was looking rather spindly.  Surely these tiny moths couldn't have found such a pathetic specimen of a Fig?  Well amazingly I was wrong... I found 3 Choreutis nemorana cocoons on it and the plant only had 7 leaves! 

The school Fig - a feeble specimen!

Over the last couple of weeks I have attempted to spread the word and encourage people across the country, especially up the East coast, to check every Fig tree they come across and look for signs of this relative newcomer to Britain as it tries to establish itself here. Coincidentally, there is a country-wide survey of a couple of moths including C.nemorana and all records and photos of possible candidates should be sent to Colin Plant on