www.ukbutterflies.co.uk

Hi Pauline

It looks like you are having more success than me, great images . Those Elm flowers are spectacularly colourful in close up.

Hi Pauline,

I am very impressed with your images of the WLH eggs and larvae. Do you think the larvae have emerged prematurely? The way they are developing makes me think they could become adult butterflies by the end of May

ATB

Peter

Hairstreaks only have 4 instars and can develop very quickly, i have known Brown Hairstreaks go through in May, even in outside conditions, it doesnt make much difference if there are a few of them as they can breed and lay eggs that will overwinter, so the following year will be back in sync. These were rescued eggs, so they woundnt have gone through at all if they had been left on the ground.

I think in captive outside conditions often netted the larvae feel safer and eat a lot more often, hence they speed up.

White Letter Hairstreaks have a long flight period, from mid-June through to late August, so there is hatchings over all over that period, so it seems to be the larvae hatch over 3 months in the Spring. Later hatching larvae must start feeding on leaf buds.

As Elm flower buds are breaking now the eggs have to hatch in sync with those, or when the seeds drop off in a few weeks the larvae will be on the floor, so they need to have moved onto the leaves when they open.

Thank you for the complement Paul. If you should happen to read this I'd be interested to know what state your local Elms are in currently? Must be a couple of weeks since you asked me to check out one of them and I was able to report that the buds were bursting.

I'm pleased you like the images Peter - it is lovely to hear from you. The Elms at Cosham have been in bud for several weeks now and the leaves are starting to unfurl. Indeed I am finding it a struggle to obtain branches in flower as the flowers seem to be dying back and in desperation I am bringing back branches with leaves. I believe that one of Paul's eggs (from the same venue) hatched a couple of days after my first one - and I believe he kept his in the fridge. Having made this mistake before I am keen to try to get the timing right and I can only stress that I am doing my best with some guidance. Let us hope it all ends well, eh? I appreciate your input.

Thank you too Martin - I have emailed you.

It is good to think about these things and question oneself. It has caused me to remember that my first WLH sighting at Cosham in 2014 was on the 14th June and again on 15th June. I didn't manage to get a photo until 18th June and if my memory serves me right this went down on the record as the earliest sighting in the country so perhaps Cosham is a particularly early site? Last year I did not get to visit until later in June (about 24th I think) and they were already on the wing.

Pauline wrote:Thank you for the complement Paul. If you should happen to read this I'd be interested to know what state your local Elms are in currently? Must be a couple of weeks since you asked me to check out one of them and I was able to report that the buds were bursting.

Hi Pauline

As you know I am actively seeking out prospective Elms locally for White Letter Hairstreak. The flowering Elms I have found locally are a mixed bunch at the moment and range from completely covered in open flowers to no open flower buds at all. Unfortunately I have found Elm to be a difficult tree to accurately identify at species level. There are 2 Elms locally (which look to be the same species) that from past experience are always completely covered in seed from top to bottom, at the moment neither of these has any open flower buds. One is in pretty much full sun and the other is much more shaded. A newly found Elm (which looks ideal for White Letter Hairstreak) which is a different Elm to the previous 2, currently looks like it is at the height of flowering and could have finished in a couple of weeks! Another newly found Elm which I examined last Sunday is different species again and looks to be well covered in flowers, it is partly in sun and partly shaded but is very difficult to access. The more familiar Hedgerow Elm where it occurs seems to be only just starting to flower. So it seems that timing varies greatly between different species and location, plenty of scope for study here I think.

Pauline wrote:I'm pleased you like the images Peter - it is lovely to hear from you. The Elms at Cosham have been in bud for several weeks now and the leaves are starting to unfurl. Indeed I am finding it a struggle to obtain branches in flower as the flowers seem to be dying back and in desperation I am bringing back branches with leaves. I believe that one of Paul's eggs (from the same venue) hatched a couple of days after my first one - and I believe he kept his in the fridge. Having made this mistake before I am keen to try to get the timing right and I can only stress that I am doing my best with some guidance. Let us hope it all ends well, eh? I appreciate your input.

Yes you are quite correct Pauline. Of the four eggs I have all were initially kept in the fridge, one hatched on the 26th Feb in the fridge! They are all now outside unprotected, but the three remaining eggs are unhatched. Interestingly the Elm twig that my larva is on (it put in an appearance late last night) has been in water for 3 weeks and is still viable as food.

Thank you Paul for that comprehensive assessment. As you say it is not really conclusive and how far the trees are advanced probably depends on many factors, even in the same locality. Most of my branches are not lasting too long and I am wondering if it is because most of them are in Oasis (foam) as opposed to water as I am now afraid I will drown the little cats as 2 of them have taken to wandering. The branches that are lasting are now developing green seed pods (is that the right term? ). Today I spent some time checking these branches as I have not seen No 3 or No 4 since they hatched. I am pleased to be able to report that I located all 4 cats. No 2 and No 4 did not seem to want to pose for the camera but I managed to get a few shots of No 3 - the first since he hatched. He is now 5 days old but still extremely tiny and very well camouflaged - in fact he looks like he has been sprinkled with icing sugar:

It is snowing quite heavily as I type this which I expect will slow the cats development down somewhat. I found No 1 who is now 11 days old exploring today and although he ended up back on his bud - still well camouflaged - I don't think it will be too long before he shows more interest in the leaves
Just wanted to show the 'context' with these last couple of shots and despite the changes in the cat try to demonstrate how well he still fits into his environment.

I shall try not to indulge myself on a daily basis, but then again, I find these cats so interesting it is hard to resist getting the camera out once I have actually found them, so who knows . No. 3 surprised me today as he seems a different colour from No 1 at the same age. He is very much a brownish colour rather than the pinkish tones of No 1. He is quite active so I am assuming nothing is amiss and perhaps this is just a natural variation or perhaps he is preparing for a moult. I shall have to wait and watch. At 6 days old he is still very tiny (I am sure No 1 was bigger at his age!)
No 1 continues to munch his way thru most of the day and he now seems to be eating seed pods. At least I think that's what they are? I am guessing that this is a transitional phase between the flower petals and the leaves - or perhaps he is just desperate as he hasn't had any fresh branches lately:

Hi! pauline, No 1 looks like he's partly Brown and Green, or, it's my eyes Goldie

He is now Goldie, but he didn't start off that way. He was quite small to begin with and more of a pinkish/brown colour. Here is No 1 at 4 days old:
I have been quite concerned about all 4 cats over the last few days as they have all been very inactive and not eating. Although No 1 hatched 5 days earlier than No 2, the size discrepancy is quite marked, although they have been treated largely the same. No 3 and No 4 do not appear to be thriving as I would expect and last night I was convinced they were getting smaller, leading me to think that they were about to shrivel up and die . There are no buds left at Cosham (the flowers are all dying off now) so I had to find a source elsewhere - just to prove to myself that I wasn't starving them. Whilst scrutinising their buds I found a caterpillar crawling all over them. It was very fast and gave the appearance of sliding through the foliage rather than crawling but kept returning to the cats. If anyone can identify it I would be very interested:
This is No 2 at 10 days old:
By comparison, this is No 1 today who has now thankfully started to eat again:
No 3 and No 4 have been like this for a couple of days. Their flowers are as good as dead but I can't transfer them to the fresh food supply until they start to move:
I find it strange that they are clearly developing at such different rates despite their similar environment.

Strange isn't it Pauline, also very interesting, I hope they continue on Okay, keep us posted.

I saw my first Butterfly Yesterday, I say first, I tried to take the photo of two before I finally managed the one a Small Tart, mind you it could have been the same one coming back. Goldie

Goldie M wrote:Strange isn't it Pauline, also very interesting, I hope they continue on Okay, keep us posted.

I saw my first Butterfly Yesterday, I say first, I tried to take the photo of two before I finally managed the one a Small Tart, mind you it could have been the same one coming back. Goldie

Thats an interesting species a Small Tart, I know her sisters Scarce Tart and Large Tart

Excellent baby WLH! I reared the caterpillar last year but not from this early stage - I had not appreciated that the first-instar caterpillar is brown-grey, probably to camouflage it against the elm twigs I would imagine. This butterfly is a true master of disguise in all its stages and the caterpillars mimic the appropriate parts of the plant so well.

The other larva you found on the elm could well be the scarce Dusky-lemon Sallow, or its commoner relative the Brick (which in my limited experience on a different foodplant looks a little different to yours at this point; they change colour as they get older and I believe both end up looking like the Brick larva photographed below). Definitely worth rearing through - if the former your county moth recorder would be most interested. I reared Brick moths from larvae on fallen sallow catkins last year, and the larvae are very enjoyable, looking like tiny adders, and to an extent behaving like them too, moving in quite a serpentine way around the catkins.

Moths in this family have a reputation for eating other caterpillars, so it is probably worth rearing it separately to your hairstreak larvae.

Interesting stuff Pauline - looking forward to the 'end results'
Have a goodun

Wurzel

Hope you get the cats separated in time Pauline Goldie

Thank you for your comments Goldie. As you already know I did separate the 'intruder' immediately but seem to have 'lost' him which is a real shame given Matsukaze's comments. Well done, spotting a 'Tart' - not a butterfly I have ever come across Their range must be restricted to the North

Seems like I'm the only one who hasn't seen any 'Tarts' Martin

Thank you Wurzel - I'm fascinated and hope the 'end results' are all I could have hoped for.

Great to hear from you Matsukaze and thank you for your interesting and informative post. Your description of 'serpentine' is spot on. I was going to describe it as 'snake-like' but thought that would sound daft. However, it really seemed to slither rapidly around and in and out of the bud in a way I have not seen before, poking its head through the petals. It was so attracted to the tiny cats that I immediately put it on a different Elm branch outside - foolishly without any protection - and now I can't find it again . Having looked up the Dusky-lemon Sallow and the Brick there seem to be subtle differences between the two and it was definitely more like the Dusky-lemon Sallow. I shall keep looking. I was interested to read that you had reared WLH and again you are spot on when you comment that it is 'a true master of disguise in all its stages'. This caterpillar is almost chameleon-like and seems to be able to blend in impeccably with any part of the plant. I was thrilled to be able to see several emerge from the egg - photos on previous page. Thank you again for your comments Matsukaze.

Of my 4 WLH cats, 3 are what I would consider to be probably 'normal' size, ie. they are still really tiny. However, the one which emerged about 5 days before the others is massive - about 10 - 12 times larger - and spends all of the time eating. He was very active yesterday so I don't think he has undergone another skin change but overnight the brown colouration seems to have completely disappeared (although this seemed to be gradually fading). He is very active again today but I am wondering if he could have shed his skin overnight? I shall try to post photos later.

Looking at my own photos it seems that the head of No 1 is very small in comparison to his body size so I am assuming that a skin change is imminent. Peter's concerns at the rate of development of this cat were clearly valid but I am at a loss to understand why he is developing so fast relative to the other 3 and how I can (safely) slow this down. Here he is this morning:
.... and this is No 2 (No 3 and No 4 are also this diminutive size):

I have really enjoyed catching up with your diary and seeing your caterpillars. It is all really interesting. I haven't had any caterpillars to keep me occupied over the winter. Sadly nothing seemed to lay any eggs in my garden last year. Still, shouldn't be too long before I see my first butterflies!

This particular caterpillar might be more advanced for a few possible reason, these are my own thoughts -
Mustard-oil glycosides dictates Small Whites and Large Whites eating behaviour, which is present in the brassica family, as a type of stimuli it naturally produces the biting responses associated with eating, aiding survival rates, focusing on the plants which contain the appropriate nutrients to aid caterpillar development. This might be the same with Elms and the White-letter Hairstreak, hard to know without the scientific evidence of what the leaves contain. It might be a possibility that the seed pods contain more nutrients than the flowers, if it's eating on this it could be the reason it's developing at a faster rate. The green colouration makes sense for when feeding on the seed pods, as others have expressed they have superb camouflage and change with ease to suit their surroundings. Other than this it could simply be that this individual is going to emerge as an adult before others, their emergence has to be staggered to produce sighting from late June to early August. It will be interesting to see if this one will be a male, females appear to emerge later. Everything I've written are just personal theories. P.S. I've been following your posts on their development very closely, superb documentation and photos, your doing a fab job! Thanks, Jamie

Pauline, I know why your cat is so big, he's been eating the Tarts Sorry, couldn't help that! Seriously now Can't wait to see the next posts, Goldie