www.ukbutterflies.co.uk

Edit - 29th October 2012: This is the diary version of this project. A fuller detailed version with additional information and images can be viewed here:
viewtopic.php?f=37&t=6598

Earlier in the year, during the course of my Brown Hairstreak egg survey for the Sussex Butterfly Atlas, I found a number of eggs on severed stems. These were rescued and I am now raising them to adulthood for eventual release to their original sites. These have now all hatched and I found the first of the young larvae today. This one is 4 days old and 2mm long.
This is my first experience raising Brown Hairstreaks and I am looking forward to the task. I usually compile a full species report after the adults have flown, but in this instance I will provide regular updates, particularly during the early instar stages.

Vince

That's a corker of a photo, Vince!

I am sure you will enjoy raising the little chaps, it is a very rewarding experience.

Thanks Susie. This little guy owes you his life. If you had not reported that your eggs had hatched on 7th April, I would not have attached the stems to the Blackthorn plants in time. When I checked my eggs on 8th April, one of them had a hole in it but luckily the the larva was still inside. The other two hatched on successive days.

Vince

I reckon you ought to call it Susie if it doesn't have a name already, and if it turns out to be male then it can be a boy named Sue and rougher and tougher than all the other brown hairstreaks ...

I have now found all three larvae in their respective leaf buds (plus a Sawfly larva which was confusing for a while). I do not tend to name my larvae, but they each have a designation for record keeping purposes (L1-L3), with the 'L' standing for 'Lucky' in this case (thanks to Susie). All are acting slightly differently. The first one to hatch has tended to stay inside the leaf bud, the second is half in and half out, while the third has stayed in a fairly exposed position out on a leaf. This leaf has started to curl over, so he is now slightly more protected. Given this bold behaviour he deserves a bold name, so Sue it is.
He is now 6 days old and you can see that he has been busy since the last photo.

Vince

Hi all,

Here is the latest update on Sue and his two siblings. All are doing very well and are to be found on the undersides of their respective leaves or leaf stems when not feeding. You can see different types of feeding damage on the leaves including zig-zag browsing on the underside of the leaf above. All three larvae have doubled in length in the last 6 days and have now taken on a different shape, appearance and colouration. One other observation is that they are a much paler green than I was expecting which makes them stand out quite strongly when out in the open.
More updates soon.

Vince

Just a quick update, now that my larvae are a month old. I have two on one plant (L2 and L3) who are both around 10mm long now. The other (L1) began acting strangely one day and then went missing for two and a half days (I do not cage or net my larval plants, but keep them under cover in a sheltered spot). I eventually found it a few feet away on the edge of one of my Orange Tip pots, having lost a bit of size. Now that it is back on its own plant it has quickly recovered and is matching the size of its siblings.
You can see where they have been feeding overnight before returning to the underside of their respective leaves to snooze and where they are impossible to spot when in shadow.

I know that they change colour when they are about to pupate. Can any one advise whether they also stop feeding at this stage and how long after the colour change do they descend to pupate in the ground?................ Pete or Susie?

Vince

Vince
I am finding this thread fascinating.
Your photos are also excellent.
Please keep the updates coming.

From memory mine didn't stop feeding until they suddenly started to disappear and I found them at the bottom of the pot on and in the soil. I cannot remember them changing colour prior to going to ground (I wish I had taken more detailed notes at the time) but once on the ground they rapidly became pink, took position and started to shed their skins ready to pupate. I have a photo on the brown hairstreak thread which was running at the time showing them at this stage.

Edit: Unfortunately the thread doesn't show the photo I had in mind. I'll dig it out.

viewtopic.php?f=21&t=2894#p22753

One of the things I found interesting was that I was able to time almost exactly to the day how long they would feed for and how long they would pupate for. It was very exact.

This year I didn't net my pots either and I haven't been able to find any larvae on my blackthorn recently.

Vince,
Those last pictures are fantastic. Nice that the caterpillars have found such a good nursing home Looking forward to more pictures as they grow.
Michael

Found it! You can see it is still a tad green along the top.

Thanks Roger, Susie and David for the comments and advice. I have just ordered some netting to ensure that they do not wander off before they pupate. I will keep you all updated with the latest news and developments.

Vince

Vince Massimo wrote:I know that they change colour when they are about to pupate. Can any one advise whether they also stop feeding at this stage and how long after the colour change do they descend to pupate in the ground?................ Pete or Susie?

Apols Vince - only just seen this! An obvious conclusion is that the colour change is beneficial when the larva starts to move off of the leaves and down the branches to the ground. Movement off the leaves is therefore imminent!

Cheers,

- Pete

I found one of my brown hairstreak cats this afternoon. It too is only 1cm long.

Update time again, because things are moving quite quickly now.

To summarise - The three larvae hatched on sucessive days. L1 on 9th April, L2 on 10th and L3 on 11th which makes them 36-34 days old respectively. As they developed, their sizes reflected this staggered hatching until L1 went AWOL for two and a half days when it could not have fed and has now slipped behind the others. L2 is now the largest, having suddenly increased in length to 15mm, with L3 slightly behind at 12mm. I know that L3 has recently moulted and should soon catch up. I think both L2 and L3 are in their final instars and the books say that pupation should take place between 40 and 60 days after hatching. Although L1 is the oldest, it has not been feeding for as long and so is only 10mm long.

Today I took some comparative photos of L2. Most of the photos I have posted so far are not true to nature, because they have either been taken with the larva in full sunlight, or with flash, and always looking from under the leaf on which it is resting. These do not reflect what a predatory Blue Tit would see.
I still do not believe I have captured the essence of just how well they are concealed, but hopefully you get the idea.

I fear I may miss some interesting developments when I go away on holiday for few days at the end of the week, but will report anything that changes before then.

Vince

Susie wrote:I found one of my brown hairstreak cats this afternoon. It too is only 1cm long.

Susie, how big do you think it would normally get before it is ready to pupate? I am still trying to fully understand the sequence that leads up to pupation. (Size of larva/behavioural changes/colour changes etc). Particularly, I am still not clear if the colour change starts when the larva is still on the leaf.

Vince

I was surprised by how small this chap was today. I reckon it will be almost twice this size before it is ready to pupate if memory serves correctly regarding the previous ones I had. I remember they were chunky wee beasties before they changed. I think they go to ground and then change colour but perhaps subtle changes occur and so they know it's time to move.

Vince Massimo wrote:I still do not believe I have captured the essence of just how well they are concealed, but hopefully you get the idea.

Their camouflage is staggeringly good!

Lovely pictures Vince.

Cheers

Lee

A very interesting day today. On 26th May, upon returning form a few days away, I found that the 3 larvae had bulked-up considerably and were all looking very chunky. They were only on a small plant and had eaten most of the leaves. The remaining leaves were barely large enough to conceal them.
I transferred them to a larger plant that same day, ensuring that they had enough dry leaf-litter at the base of the plant. Two days later the largest larva (L2) went missing. There was no way it could have got out of the netting, but I searched the shed nonetheless and found nothing. Hopefully it was in the leaf-litter preparing to pupate, but I was loath to disturb it. Today I gave in to my curiousity and carefully started to inspect the leaf-litter. Nestled under a dry leaf was the larva which had completly changed colour. I was expecting some sort of subtle indication that it was going to change, but this was not the case. One day it was green and hanging under a leaf and the next it was gone.
Pupation is expected so, expect more updates in the coming days.

Vince

This is fantastic stuff, Vince! I've only observed these in the wild and when it gets close to pupation time I stop looking, so as not to tread on the pre-pupae/pupae. I look forward to the sequels.

Guy