www.ukbutterflies.co.uk

Roger Gibbons wrote:From the other end of the supply chain here in south-eastern France, I have seen considerably more LTBs in the past couple of years than in the previous decade. I used to see maybe one or two each year but latterly maybe ten or so.

That's an interesting observation, Roger, as it seems to contradict any notion that the species is moving northwards at the expense of its Mediterranean range.

Perhaps it is becoming commoner in the southern area of Europe (for reasons we don't yet know), and that is having a knock-on effect on numbers further north?

Thanks, Roger. That's very interesting and fits nicely with the bigger picture which I suspect is behind these recent, happy events.

David: "it seems to contradict any notion that the species is moving northwards at the expense of its Mediterranean range" The idea that this species might be abandoning its traditional homeland, because it might be able to survive year-round at increasingly northerly latitudes seems quite a strange one to me - and very risky for a species. Do you have any data which supports any suggestion of reduced numbers in the Mediterranean zone?

BWs, Neil

Neil Hulme wrote:it seems to contradict any notion that the species is moving northwards at the expense of its Mediterranean range" The idea that this species might be abandoning its traditional homeland, because it might be able to survive year-round at increasingly northerly latitudes seems quite a strange one to me - and very risky for a species. Do you have any data which supports any suggestion of reduced numbers in the Mediterranean zone?

No, Neil. It's just a postulation based on some of the comments that have been made (i.e. that global warming is potentially shifting this species further northwards).

To my knowledge, it has historically been a Mediterranean insect, and its migratory forays further north are largely dependent on weather conditions. I personally don't see how this will change unless there is a major climatic event, which would probably take decades to unfold properly.

What's interesting to me (having just read Matthew Oates' book) is how it appears to have temporarily colonised southern England in good numbers twice in three years having been an exceptional immigrant previously.

Hi David,

"To my knowledge, it has historically been a Mediterranean insect". The Mediterranean is the just the northern tip of its traditional zone of residency, which extends southwards over the whole of Africa.

"its migratory forays further north are largely dependent on weather conditions". I'd be interested to hear your assessment of the weather conditions this year, which would have triggered (another) unprecedented event of this nature.

"I personally don't see how this will change unless there is a major climatic event, which would probably take decades to unfold properly". It would therefore be very difficult to explain away the discovery of Provencal Short-tailed Blue in Normandy this year!

BWs, Neil

The Mediterranean is the just the northern tip of its traditional zone of residency, which extends southwards over the whole of Africa.

I'm referring to its European range here, Neil. I'm aware that it exists far more widely than that, but I doubt that sub-Saharan insects venture into southern Europe (although I'm prepared to be proved wrong).

I'd be interested to hear your assessment of the weather conditions this year, which would have triggered (another) unprecedented event of this nature.

Weather conditions in southern France have been abnormally hot in summer 2015. However, they were hotter still in 2003 yet this didn't result in similar numbers of LTBs arriving in England.

It would therefore be very difficult to explain away the discovery of Provencal Short-tailed Blue in Normandy this year!

That's news to me, Neil (albeit very positive news). I knew nothing of this phenomenon until your last post. Please tell us more.

Hi David,

"I'm referring to its European range here, Neil. I'm aware that it exists far more widely than that, but I doubt that sub-Saharan insects venture into southern Europe (although I'm prepared to be proved wrong". The African range of LTB is not sub-Saharan, it continues all the way up to the north African coastline, just a short hop from southern Europe. But of course butterflies don't recognise geographical terminology, so this is all one contiguous range zone.

"Weather conditions in southern France have been abnormally hot in summer 2015. However, they were hotter still in 2003 yet this didn't result in similar numbers of LTBs arriving in England". Which rather argues against the theory that weather (not climate) patterns alone are entirely responsible for such phenomena.

"That's news to me, Neil (albeit very positive news). I knew nothing of this phenomenon until your last post. Please tell us more". This is a 'pers comm.' from one of the world's leading experts on the influence of climate change on our Lepidoptera, who may wish to publish on it, so I won't say more until I clarify his plans for the data.

I've had a bit of time off tonight, and much as I enjoy a good debate on some of the more exciting events we have been seeing in recent years, I must reiterate that generally I'm too short of time to indulge in such discussions at the moment. For now at least, I would ask that this remains a Personal Diary in content, and that discussion topics are started as different threads.

BWs, Neil

I have noted your comments regarding the integrity of your PD, Neil, and assure you that this will be the last comment I make here regarding Long Tailed Blues.

You've left me a little perplexed. First of all, you said:

Neil Hulme wrote:The Mediterranean is the just the northern tip of its traditional zone of residency, which extends southwards over the whole of Africa.

Yet in a subsequent message you posted this:

Neil Hulme wrote:The African range of LTB is not sub-Saharan, it continues all the way up to the north African coastline, just a short hop from southern Europe.

Surely those two statements are contradictory?

Hi David,

No, they are entirely consistent with each other. The historical zone of permanent LTB residency extends from the Mediterranean belt, down through the northern coastline of Africa and down through the rest of Africa, i.e. there is no separation between the Mediterranean 'population' and a sub-Saharan 'population', as clearly implied by your statement: "but I doubt that sub-Saharan insects venture into southern Europe".

BWs, Neil

Long-tailed Blue; Emergence Of The Brits

The eagerly anticipated emergence of British Long-tailed Blues has begun. This morning (19 September) I headed out feeling quite confident of seeing my first home-grown specimen of the year. The timing of this entire event has borne an uncanny resemblance to proceedings in 2013, so it came as no surprise when I struck gold just one day later than my first sighting of a ‘Brit’ at Kingsdown Leas that year.

Based on the 2013 model, it was also unsurprising that the females have emerged first, which is of course the opposite pattern to that observed in most species. This year I also hope to be able to test my theory that, once mated, the females will immediately turn south and depart for their homelands.

I chose Newhaven Tide Mills as a venue, as my study of Sussex Long-tailed Blue ova has suggested that this site was visited by the earlier part of the main influx, before it stalled for a significant period due to bad weather in August.

At about 11.15 am I flushed a female from a stand of Broad-leaved Everlasting Pea and had the best part of 10 minutes observing and photographing her, before her rapid, twisting flight threw me off her trail.

I thought I had relocated the same insect at c. 11.30 am, but didn’t manage to photograph her before she looped up high over an extensive area of bramble scrub and disappeared from view. This later proved to be a second, freshly emerged female, with a distinctly duskier upperside.

Having put the news out to a few friends I became worried that I would have nothing to show on their arrival. Moving around to the other side of the bramble patch I began to systematically scan every leaf for sight of her. After 20 minutes I noticed her sitting only a couple of metres away, just as B. rex and Trevor appeared over the horizon. We were later joined by Mark Colvin and Badger Bob, who all enjoyed wonderful views of this perfect specimen before we lost track of her at c.1.15 pm.

I was pleased that a reasonable number of people were able to share in the excitement, including all those who have invested a lot of time in searching for the primary immigrant adults and their eggs.

Only time will tell if the 2015 influx of Long-tailed Blue will produce more adult sightings than the unprecedented 2013 invasion, but on present form it could be neck-and-neck.

HI Neil,
Many thanks for sharing that beautiful LTB yesterday, i had a fabulous day that i will remember
for a long time. Also a day spent in great company.

Best wishes,
Trevor.

Marvellous report and photos Neil. I have to say that few people would have been as diligent in their searching and getting due reward.

So the question: could it be that LT Blue immigration and late season breeding is much more regular than had previously been thought and that until now, observer skill and perseverance in tracking them down had been lacking?

Jack

Hi Neil,

Wonderful LTB reports and superb photos. I wonder if this influx becomes a more regular event if they may start to come a bit further inland in the future, perhaps even as far as the midlands.

Cheers,

Neil

Trevor: Glad you were able to get there and enjoy what must go down as a season highlight for us all!

Jack: I think it's a bit of both. Major changes seem to be occurring (look at gorganus Swallowtail too), but I'm sure that observer effort and focus has increased and it is likely that small scale events have been overlooked in the past.

BWs, Neil

Thanks, Neil. I think incursions will eventually strike deeper, but you'll probably have to travel south at least until you've gone completely grey. The odd one has managed to get quite far north in the past, so if we were to get a particularly large influx coinciding with an Indian Summer, you might just get lucky.

BWs, Neil

Lovely Photos Neil, your so lucky living in the South, I don't think those LTB's would fly so far North, I'll just have to visit relatives later in the year Goldie

Hi Neil
Lovely images of the Long Tailed Blue I just wish I had a bit more time on my hands. I received your PM but am unable to send reply (PM disabled) can I email you the information?

Thanks, Goldie and Paul.

Paul, I've just sent you a PM with a direct email address.

BWs, Neil

I have to wonder Neil given your record in finding (or seeing) rarities - LT Blue, Queen of Spain, Large and Scarce Tortoiseshells, Continental Swallowtail, Camberwell Beauty – what your next find will be?

Is it possible that for example Short-tailed Blue lurks undetected somewhere? It would be very easy to overlook and if anyone can track it down, I’m sure you are the person to do so.

Jack

Thanks, Jack. I suspect that Provencal Short-tailed Blue or Southern Small White might take us by surprise. Oh, and you forgot to include my Monarch (but not the dodgy geezers from Brighton, which I don't count).
BWs, Neil

Coldstream Guards On Parade

A brief visit to Beeding Cement Works this afternoon (29 October) failed to locate any Long-tailed Blues, but I was more than happy to find half a dozen beautiful Red Admirals feasting on the ivy flowers. Sunny autumn days wouldn't be the same without them.