Yellow-legged Tortoiseshell Invasion in the Netherlands!

[David M]

Actually, I ask myself a question if anyone knows where its distribution range approximately ends. Given the fact everything eastwards from CZ is vaguely or poorly explored.

According to my Tolman & Lewington, Yellow-Legged Tortoiseshell is very much an eastern European insect. It's permanent distribution has a westward limit of Slovakia, southern Poland and the very eastern margins of the Czech Republic.

That said, there is an orange shading to denote those areas into which it regularly migrates. This area includes the Baltic states and Slovenia, but nowhere is there a suggestion that it makes its way into western Europe, which is why this invasion is proving so notable.

[Padfield]

Ssp. xanthomlas flies as far east as China and Korea. There are three further subspecies, fervescens, japonica and formosana. The last two are self-explanatory. Ssp. fervescens flies in Turkey, Transcaucasia, Iran, Iraq, Turkmenistan, Afghanistan, Pakistan, India, Tibet, Kyrgyzstan, Tajikistan, Uzbekistan and Kazakstan. Basically, the species flies in the whole of Asia (Information from Bozano, Guide to the Butterflies of the Palearctic Region).

Guy

[PhiliB]

At 6am this morning Rosalyn & I decided to try and twitch the Costessey Scarce Tortoiseshell.
We managed to get a few shots of it up in an oak tree at around 11am when it made its first, and only, appearance. It stayed there for about half an hour before flying off, not to be seen again.
The photos are a bit rough but this individual showed enough leg for us to get a positive ID.

The local lads who found it are convinced that it is a migrant and not a local release. It spent Sunday & Monday continually feeding on buddleia, yesterday it fed more leisurely and today it appears to have continued its journey west.
Phil

[HarassedDad]

So now the question is: how long before we get photos of one ovipositing?

[Jack Harrison]

So now the question is: how long before we get photos of one ovipositing?

Haven't they got to overwinter first? Or are they double brooded like Comma?

Having been following this thread from afar, I would think that the Sandwich sighting rules out the release hypothesis.

Digress. When might the next generation Swallowtail gorganus emerge if indeed they bred this spring?

Jack

[Mikhail]

This extraordinary sight may help to explain the current Drang nach Westen: http://www.lepiforum.de/lepiwiki.pl?Nym ... anthomelas. Scroll down to Biologie and click on the right hand photo.

M.

[Mark Tutton]

Wow i think the name 'Scarce Tortoiseshell' is somewhat inappropriate given these photos!

[Neil Hulme]

Hi Jack,

I think the funeral release hypothesis was scuppered as soon as we were aware that there had been a well documented, large scale invasion of NL, and the first individual had been positively identified as xanthomelas in the UK (locally); at which point the chance of this species turning up in the same area as the result of the former theory (without any evidence that this species has ever been used for such purposes) would be many orders of magnitude smaller than for it being a genuine visitor. Poor old Ockham would turn in his grave! Mikhail offered to eat his Tilley hat; I'd have eaten the table it was sitting on.

As for gorganus, any progeny of the spring/early summer UK brood should emerge (mainly) in August, although the events are likely to be protracted.

BWs, Neil

[The Annoying Czech]

Actually, I ask myself a question if anyone knows where its distribution range approximately ends. Given the fact everything eastwards from CZ is vaguely or poorly explored.

According to my Tolman & Lewington, Yellow-Legged Tortoiseshell is very much an eastern European insect. It's permanent distribution has a westward limit of Slovakia, southern Poland and the very eastern margins of the Czech Republic.

That said, there is an orange shading to denote those areas into which it regularly migrates. This area includes the Baltic states and Slovenia, but nowhere is there a suggestion that it makes its way into western Europe, which is why this invasion is proving so notable.

Now, according to that German site, I see guy a was in contact with once, Andrej Makara, snapped YLT twice this year. And since I know his home place, I see he didn't have to seek that much for YLTs, just probably made a nice one-hour walk around his village. From that I assume there is many YLT undiscovered sites across Slovakia, either connected with this year's massive migration/expansion or being there on a long-term basis.

The thing is, Slovakia, although very small and very diverse (like 10 times smaller and 3-4 times species-richer than UK), remains quite unexplored with some unclear extinctions or unsure status of "bordering" species just as Limenitis camilla, Libythea celtis or now discussed Nymphalis xanthomelas. Which is quite unbelievable for us Czechs as we have pretty well covered almost all problematic species worthy to watch or conserve.

As information about "eastern countries" in "western books" are often wrong, or somehow misguided, I can assure you there were no stable YLT populations in the very eastern margins of CZ at least for decades. And I myself haven't seen any in my life, despite living less than 50 km from Slovakia/Poland and travelling south around the border for a long time. I'd actually like to say the opposite but that's just how it is.

If I see any migratory individual during my planned three days long Tour de Czech Rep., I will let you know though !

[lazarus]

Remember that there was also a record from the Shetlands in November 2013, viewtopic.php?f=8&t=7273&start=40#p78966 and an anomalous tortoiseshell viewtopic.php?f=8&t=7466 earlier this year. I wonder whether these records have anything to do with the current influx? If not, it does seem an enormous coincidence...

[knotsbirder]

Remember that there was also a record from the Shetlands in November 2013, viewtopic.php?f=8&t=7273&start=40#p78966 and an anomalous tortoiseshell viewtopic.php?f=8&t=7466 earlier this year. I wonder whether these records have anything to do with the current influx? If not, it does seem an enormous coincidence...

Shetland individual was found in imported lumber and the one earlier this year could have been anything. I'd be surprised if either had much to do with it at all.

Sam

[HarassedDad]

I have another. Report with photo's of a YL in a garden in Hoveton, Norfolk yesterday.

[Paul Wetton]

I'm hoping to head over to Norfolk this weekend.
If anyone knows anyone with a Y L Tortoiseshell visiting their garden and wouldn't mind someone filming it in exchange for a free "Butterfly Year" DVD please PM me as I'd love to get some film of one of these beauties.
Thanks

[lazarus]

Shetland individual was found in imported lumber and the one earlier this year could have been anything. I'd be surprised if either had much to do with it at all.

But it is still a peculiar coincidence, that after no activity at all for sixty years, these reports occur so close to the recent influx..

[kentishman]

.... and now Essex!
https://twitter.com/Boudicca_1970

[HarassedDad]

Anyone coming to Norfolk at the weekend is welcome to ring me for an update on saturday - 07759892597

YL may not be the only species coming over.

[chrisvanswaay]

Check out this animation of how fast this species colonised Sweden within three years:

http://larspett.cartodb.com/viz/1985786 ... _options=1

[Gruditch]

In the Mail online today.

http://www.dailymail.co.uk/sciencetech/ ... -1953.html

Regards Gruditch

[Jack Harrison]

Check out this animation of how fast this species colonised Sweden within three years:
http://larspett.cartodb.com/viz/1985786 ... _options=1

Any computer whizz out there who could produce a similar PREDICTIVE map for the British Isles 2014 to 2017?

Jack (Dreaming. But you never know)

[nomad]

I enjoyed the pics of this species taken by K Heaven in a garden at Sandwich - Kent and tweeted by Matthew Oates on Wens. The photographer was very lucky.